April 17 has come and gone and you've probably had enough of tax season.

But don't put those tax files away just yet. Now's the time to begin tax planning for your 2007 tax return.

"One of my favorite quotes is, 'Only turkeys do tax planning after Thanksgiving,' " said Paul Mueller, the CEO and managing director of the District of Columbia office of UHY Advisors, a tax and business consulting company. "You now have another eight and half months of the tax year left. Do some tax planning while everything is fresh in your mind."

If you got a lot of money back from the IRS, you might want to make some changes for 2007, Mueller said. "A lot of people think it's good news to get a refund," he said. "What it really means is you made an interest-free loan to the government."

The IRS reports that the average refund as of April 6 was $2,366, up 3.3 percent from last year's $2,290.

Certain events can change your tax situation, resulting in a larger-than-expected return — purchasing a home, having a baby or getting married. However, if year after year you're getting $2,000 or more in refunds, you need to change the withholding allowances on your W-4 form, said Mueller, who is also the national director for tax services for UHY.

If you receive a salary, you can decrease the amount of taxes withheld from your pay by changing the number of allowances on your W-4 form. The allowances are based on the itemized tax deductions you can take. Those deductions might include mortgage interest, charitable gifts or deductible medical expenses. The number of allowances may be different from the number of exemptions you claim on your tax return.

Using your 2006 tax return, go through the worksheet on the W-4 to figure out how many personal allowances to take. You can also use the IRS withholding calculator at www.irs.gov.

If you're intimidated by the worksheet, at the very least increase your allowances by one or two, Mueller said.

Higher-income taxpayers should also use their current tax return to examine their potential exposure to the alternative minimum tax, or AMT, liability for 2007, recommends John Nersesian, managing director of Nuveen Investments based in Chicago.

The AMT was introduced to make sure that high-income earners didn't use tax shelters to pay little or no income tax. It eliminates many deductions and credits, increasing a taxpayer's liability. But the AMT is affecting larger numbers of middle-income individuals because the amount of income that can be exempted from the AMT has not been indexed for inflation.

Taxpayers should pay attention to 2007 changes because the AMT exemption for married couples filing jointly will be $45,000 this year, down from $62,550 in 2006, Nina E. Olson, the national taxpayer advocate, said. For single individuals, it's $33,750 from $42,500 in 2006. The decreases will result in more people being forced to pay AMT for this tax year, he said. In a temporary fix, Congress raised the AMT exemption amount only for 2006.

Nersesian said if you do fall under the AMT, you need to do some things differently than what might typically be advised. For example, instead of taking a deduction in 2007, you might want to take it next year if you think you won't fall under the AMT.

If you're an investor and suspect you might be subject to the AMT this year, consider investing in certain municipal bonds, Nersesian suggested. The interest on "public purpose" municipal bonds used to finance capital projects for state and local governments — a school building, for instance — is not subject to the AMT, Nersesian pointed out.

However, if you are hit by the AMT, you might want to avoid investing in private purpose bonds, he said. Why? Well, the interest earned on those bonds — used to build sports stadiums, for example — is tax-free unless you fall under the AMT. Of course, you always want to weigh an investment's return versus the tax savings, he said.

I know. Your head is hurting. If it is, that means you need to do some tax planning now to save yourself some bigger headaches next April.