According to the IRS, there are approximately 10 million taxpayers who requested an extension from the April 15 deadline to file a 2007 tax return. These individuals, along with an estimated 4.3 million retirees and disabled veterans who typically don’t file a return, may be eligible to receive a stimulus payment this year.

To qualify, taxpayers must have at least $1 of tax liability or $3,000 of qualifying income from Social Security, Tier 1 railroad retirement benefits, earned income, non-taxable combat pay, or certain veteran’s benefits. Those who aren’t required to file a return because their income doesn’t meet filing thresholds should use form 1040A and write "stimulus payment" at the top.

"Millions of Americans risk losing hundreds of dollars if they don’t file a 2007 return by Oct. 15," said Amy McAnarney, executive director of the Tax Institute at H&R Block. "In these tough economic times, most people can’t afford to leave money like that on the table."

Eligible individuals will generally receive between $300 and $600. Americans who file a joint return will receive between $600 and $1,200. And, those with children will get an additional $300 for each qualifying child.