Generally, the better deals are on 2009 models where both 2009 and 2010 models are available.

General Motors — Chevrolet, Buick, GMC, Cadillac, Hummer, Saturn, Saab, and Pontiac — has announced a slew of low APR loans, including many 0% deals, and customer rebates on many models. There are no special lease deals in the mix, however.

Let’s take a quick look at some of the GM deals:

Chevrolet – Cash rebates of $1500 are offered on the Chevrolet Cobalt, Aveo, and Tahoe. The Traverse gets you $2000 rebate, and the Equinox, Impala, and Equinox get you $2500. The Trailblazer has the highest rebate at $3500. Additionally, 0% APR loans are offered on nearly all models.

Hummer – Incentives on the Hummer come only in the form of factory-to-dealer cash, sometimes called “marketing support.” As you may know, this is money that a dealer can use in any way he chooses but he usually gives it to customers in the form of price discounts. The Hummer H3T gets $3500, the H2 gets $5000, and the H3 gets $6000. This could make for some nice discounts.

Pontiac – Incentives for Pontiac for September come in the form of customer rebates for all models ($2500, except for the G6 with $3500), $500 factory-to-dealer cash (possible extra price discount), and low-interest loans (2.9% for 12/36/48/60 months).

Saab – The only incentives on Saab models are in the form of high factory-to-dealer cash — $5000 for the Saab 9-3, $7000 for the 9-5, and $8000 for the 9-7X.

Saturn – In keeping with Saturn being known as a “fixed price” brand, there are no direct customer rebates but there are hidden factory-to-dealer cash that ends up being price discounts. Dealers get $3000-$3500 depending on model. 

GMC – Customer rebates are being offered on most models, such as $1500 on the GMC Canyon and Yukon, and $2000 on the Acadia. 0% loans are available on many models as well. For example, the Yukon gets 0% for 12/36/48/60 months.

Cadillac – Most Cadillac models now have some excellent rebates in the range of $2000-$3500 (the Cadillac XLR gets a whopping $10,000 rebate). Most also have alternative 0% APR loan offers for 12/36/48/60/72 months.

Buick – Buick models get direct customer rebates for September, as well as 0% APR loans on the Buick Enclave (LaCrosse and Lucerne get 4.9% APR loans).

You can get free price quotes on any of the above vehicles from Edmunds.com. The quotes will automatically include any manufacturer incentives or discounts that are currently available.

The program is officially called the Car Allowance Rebate System (CARS) and went into effect on July 24, 2009, although some dealers were offering the program earlier.

Here is how the cash for clunkers rebate program works:

Your car must be less than 25 years old. It must be driveable. You must have owned it and had insurance on it for the last year. It must have had an original 18 MPG overall city/highway fuel rating, or less.

You must trade your old car for a new car with at least 4 MPG higher rating ($3400 credit) or 10 MPG higher rating ($4500 credit). SUVs, small pickups, and minivans only require a 2 MPG improvement, and vans and large trucks only 1 MPG improvement.

The new vehicle must be a brand new vehicle that has never been titled — not a used car. The list price (MSRP) must be less than $45,000. The minimum mileage rating for a new car is 22 MPG, or 18 MPG for a SUV, small pickup or minivan, or 15 MPG for large vans and trucks.

Your clunker trade-in vehicle must be destroyed by the dealer. It cannot be fixed up and resold. The idea is to get it off the road, forever.

The CARS cash for clunkers program is funded for “only” $1 billion. The program is over when the money runs out, or on November 1, 2009, whichever comes first.

[UPDATE:  The CARS program exhausted the entire $1 billion in the FIRST MONTH. The government has now added $2 billion more to keep it going — probably only for two more months. If you are thinking of taking advantage of this program, do it SOON.]

If your car qualifies, the $3500 or $4500 government rebate on top of any other manufacturer rebates and dealer discounts can make for some incredible car deals. You might even be able to work  out an almost free car.

What’s the catch with the program? If your old car is worth more than $3500 as a trade-in vehicle, the CARS cash for clunkers program is not advantageous to you. For example, if your old car is worth $5000 as a trade-in vehicle, it’s better to accept a dealer’s trade offer of $5000 rather than accept the government’s $3500 rebate.

Here’s are some of the best deals:

By far, the best deals are on left-over 2008 models (see Leftover 2008 Models for Cheap). We’re not talking about used cars here. We’re talking about brand new 2008 vehicles that are still on dealers’ lots waiting to be sold. Some dealers have a large number of leftovers, some only have a few, and some have none. Of course your choices are limited but the prices are the best.

Next, for 2009 models, Infiniti, Hummer, Saab, Mercedes, Nissan, and Land Rover have the highest factory-to-dealer cash on most of their vehicle models — in the $2000-$9000 range ($13,000 on some Mercedes models), depending on vehicle. This is “hidden” money given to dealers by the manufacturer to help him sell vehicles. Dealers can use the money for advertising, tent sales, or discounts. Most of the money goes back to customers in the form of large price discounts.

For direct factory-to-customer cash rebates, Chrysler, Infiniti, Nissan, Chrysler, Ford, Hyundai, Toyota, and GM are currently offering the best rebates on most models. For example, Nissan has $5000 on the Armada and Titan, $2500 on the Pathfinder, and $2000 on the Sentra. Acura, GM, Mitsubishi, and Subaru also have some very attractive rebates on many 2009 models.

The best 0% APR and low interest loans are being offered by Chrysler, GM, Ford, Suzuki, Toyota, Lexus, and Land Rover. Remember, in most cases, you can’t take the low interest loan AND rebates. You choose one or the other.

The best lease deals are being offered by Honda and Acura (on a select few models and styles), BMW (some models), Infiniti, Mazda, and Mercedes. These deals have highly discount prices, low money factors, and high lease-end residuals — all of which makes for low monthly lease payments. If you are interested in leasing, make you understand how it works so that you don’t make mistakes. See LeaseGuide.com for explanations and advice.

In our opinion, the best overall deals are now on Honda, Infiniti, and Mazda vehicles. Surprisingly, the American brands, GM, Chrysler, and Ford are offering only so-so deals, not great deals.

You can get free price quotes on any of the above cars from Edmunds.com. The quotes will automatically include any cash-back rebates or discounts that are currently available.

This means that manufacturers have heaped some pretty incredible deals on those types of vehicles to help boost sales, and clear out old inventory. Deals are even better on left over 2008 trucks and SUVs.

If this is the kind of vehicle you need or want, now is an excellent time to buy.

Most of the deals end on April 30, 2009 and, as we always remind, some deals are not available in some parts of the country.

Here is a sample of some of the best cash-back rebate deals on large trucks and SUVs (2009 and 2008 models):

• 2009 Dodge Ram 2500/3500 – $3500
• 2009 Ford F-250/350/450 – $3500
• 2009 Ford Ranger – $4000
• 2009 Lincoln Navigator – $4000
• 2009 Nissan Armada – $6000
• 2009 Nissan Titan – $5500
• 2008 Nissan Titan – $6000
• 2008 Ford F-150 – $7000
• 2008 Ford Expedition – $5000
• 2008 Ford Explorer – $5000
• 2008 Ford Ranger – $4500
• 2008 Ford F-250/350/450 – $8000
• 2008 Lincoln Navigator – $7000
• 2008 Cadillac Escalade – $8500
• 2008 Chevrolet Trailblazer – $7250
• 2008 Chevrolet Silverado – $7000
• 2008 Chevrolet Tahoe – $6000
• 2008 GMC Sierra – $7000
• 2008 Hummer H2 – $8000
• 2008 Hummer H3 – $7000
• 2008 Toyota Tundra – $6000

You can get free price quotes on any of the above trucks and SUVs from Edmunds.com. The quotes will automatically include any cash-back rebates or discounts that are currently available.