There is only one file type that uses the .TAX2008 extension:
TurboTax 2008 Tax Return
Tax return created with TurboTax 2008, a program for preparing Federal and State taxes for the 2008 tax year; includes user data entered through the "Easy-Step" interface as well as official tax forms, which are automatically filled in by the program.
TAX2008 files can also be imported by TurboTax 2009 or H&R Block's At Home 2009 software. TurboTax 2008 is available in Deluxe, Premier, Home & Business, and Business editions.
Updated: July 17, 2010