Update: Apple has also added rate plan information for existing AT&T customers, even those on a family talk plan. Unlimited data works out to about a $20 premium.

Apple & AT&T announced their combo data/voice plans for the iPhone this morning, and they seem to be rather reasonable:

• $59.99 / 450 minutes of voice / 5000 night & weekend minutes / unlimited data
• $79.99 / 900 minutes of voice / unlimited night & weekend / unlimited data
• $99.99 / 1350 minutes of voice / unlimited night & weekend / unlimited data

All plans include 200 SMS messages per month, and unlimited mobile to mobile minutes.