You must start taking money out of your traditional Individual Retirement Account by April 1 of the year after you turn 70.

If, for example, you turn 70 on Oct. 3, 2008, you must begin making minimum withdrawals (or distributions, as the IRS calls them) by April 1, 2009.

The minimum annual distribution is computed by dividing the IRA's balance as of Dec. 31 of the preceding year by the applicable life expectancy. That you'll find on one of three life-expectancy tables on the IRS Web site.

Most taxpayers will use Table III. It begins at age 70 with a life expectancy of 27.4 years, which requires an annual distribution of 3.65%. By 80 your life expectancy will have declined to 18.7 years and your minimum distribution will have increased to 5.35%.

If you have more than one traditional IRA, you'll have to calculate a minimum withdrawal for each. But if you want, you can add them all together and take the money from a single IRA.

If you're still building your retirement nest egg, just follow our 6 simple rules for a successful IRA.