If you filed Form 4868, Application for Automatic Extension of Time to File U.S. Individual Income Tax Return, you must file your tax return by Oct. 15, 2008. Processing times for tax returns and stimulus payments vary. If you’re getting a regular income tax refund, the IRS will send you that refund first. Your separate stimulus payment should follow one to two weeks after you receive your refund. If you’re not expecting a regular tax refund, it will generally take a minimum of eight weeks after you file your return to get your stimulus payment. For more information, see: Stimulus Payments — It's Not Too Late