I just got off the phone with an AT&T rep.
Data plans:
Unlimited: $30. no overage charges (duh)
2GB: $25. Overage charge is $10/GB
200MB: $15. Overage charge is $15/200MB
You can switch data plans without affecting your contract (although I suppose it might affect your upgrade date if you're one of those customers who spends over $100/month and gets to upgrade after a year)
Also, you can't change your plan until June 7th (aka when the next iPhone is released).
Data plans:
Unlimited: $30. no overage charges (duh)
2GB: $25. Overage charge is $10/GB
200MB: $15. Overage charge is $15/200MB
You can switch data plans without affecting your contract (although I suppose it might affect your upgrade date if you're one of those customers who spends over $100/month and gets to upgrade after a year)
Also, you can't change your plan until June 7th (aka when the next iPhone is released).