Better camera (8MP)
Able to record in HD (1080)
Dual Core CPU
The rest is basically a few internal tweaks, faster internet, better battery life and twin antenna so you might actually get a signal now
(actually it's more to do with it being a "World Phone" so it can be used anywhere, both GSM & CDMA, which sounds good for travellers but really just means that Apple only have to make one phone for all markets now.