My predictions:
1. Faster processor. Something that can multitask.
2. Better battery. This happens with every generation pretty much.
3. Thinner frame. Back to a metal design. I see them looking like the new iPod touch only with a dark grey metal (think hematite) or maybe back to aluminum.
4. Better camera. Much better. I would guess 5MP with high-quality video support. Maybe a flash, but real optical autofocus is going to be hard in a case as thin as the iPhone.
5. Larger memory sizes. I think 16GB will be the new baseline, with 32 and perhaps 64 gig models available. Maybe they'll keep the 8 around for Walmart
available next June, along with cut-and-paste and MMS support for ALL iPhones.