Will the federal income rebates of 2008 be taxable on your 2009 federal income tax?

Yes. No. The IRS, in Notice No. CP 1378, "Understanding Your Economic Stimulus Payment", mailed to recipients of the tax rebates, states "You will not be required to report the amount of your stimulus payment as taxable income on your 2008 federal income tax return." See also: http://www.factcheck.org/askfactcheck/is_the_economic_stimulus_payment_taxable.html