not that i'm running into trouble (yet), but once youre on 3.0 how can you roll back the phone os to 2.2.1? itunes says i've got the latest OS and wouldnt let me go back. the organizer would probably let me downgrade, but it's asking for the 2.2.1 ipsw file, which i dont have anymore. can any one of you give me a hint where can i find it. thanks.