Advertising Age reports that TBWA will be handling advertising duties for the upcoming iPhone launch. TBWA, which has worked with Apple since 1997, created the recent "Hello" commercial that aired during the Academy Awards. TBWA isn't a single ad firm itself but is rather an "agency network" made up of 258 full service agencies. You can visit the TBWA\CHIAT\DAY subagency that is working with Apple here.
This being an Apple deal, pretty much everyone contacted for the Advertising Age article declined to comment.