Using iphone without a computer

Its POSSIBLE, but not recommended. I suppose you could get the Apple guys to let you activate it in the store, but you'll be unable to sync music, calendars, contacts, etc.

You could buy the music from the WiFi store, but not having a computer almost defeats the purpose.

Sync without a source of data?
How are you going to sync between two devices when you only have one?
iPhones are activated using iTunes but you could probably have the phone activated at an Apple Store (since they have a few computers).

You need a computer to update anything on the iPhone.