I have an uncle who is a car salesman, and from the weary look he gives me every time I ask him how sales are going, I know that the tax breaks from the stimulus package, the tax credits designed to encourage car buying, haven't exactly kicked in yet.

But give it time. The American Recovery and Reinvestment Act of 2009 was just signed into law on February 17.

But if you're wondering what tax credits are out there for you, and in case you're motivated to spend some money and help the economy, some of the main tax credits designed to stimulate the economy are:$8,000 to new home buyers. If you bought a house (not your second home, but your principal residence) on or after January 1, 2009, and if you buy one between now and December 1, 2009, you can take the first-time homebuyer's tax credit of up to $8,000 on your 2008 return or next year on your 2009 tax return.

"That's a pretty good one," says Kay Bell, author of The Truth About Paying Fewer Taxes and who writes a blog, Don't Mess with Taxes. "It's vastly improved on the other version. Before, there was a $7,500 first-time home buyers credit, but you had to eventually pay it back. That was a bait and switch. Basically," she chuckles, "if you're going to call it a credit, make it a credit, and they've done that, and that's a vast improvement."

New payroll tax credit of $400 per worker and $800 per couple in 2009 and 2010. "This credit would be calculated at a rate of 6.2% of earned income and would phase out for taxpayers with adjusted gross income in excess of $75,000 -- and $150,000 for married couples filing jointly," says Mike D'Avolio, a senior tax consultant at Intuit, which among other things makes the TaxTurbo software. He thinks this credit is particularly helpful because it "cuts taxes for more than 95% of working families in the United States." He says that in March or April 2009, employees will begin seeing a decrease in what's held for taxes in their paychecks.

If for whatever reason, you want to not reduce your paycheck in order to claim the credit when you file your taxes in 2009 (though there's no real credible reason to do this), D'Avolio says you would need to file Form W-4 to change the new withholding amounts.

Unemployed people can exclude the first $2,400 in benefits from being taxed. That pleases Bell, who says, "Paying taxes on your unemployment checks is a little like being kicked while you're down. I guess Uncle Sam's trying to be a nice guy, and I think that's a good move, and it probably will affect many more people than we think, given the unemployment numbers."

And for people who want to buy a car this year, from February 17 up to December 31, 2009, on your 2009 tax returns you'll be able to deduct state and local sales taxes to your standard deduction or in addition to your itemized deductions. Of course, you still have to be able to get a lender to give you money for a car loan to take advantage of this tax credit, which is still tricky to pull off in this economic climate, although not impossible. That difficulty in getting those car loans is probably why my uncle seems to be aging three months for every month that passes.

Read more WalletPop coverage of how the economic stimulus package will help you, right here.

Geoff Williams is a freelance journalist specializing in personal finance and the author of C.C. Pyle's Amazing Foot Race: The True Story of the 1928 Coast-to-Coast Run Across America (Rodale).