http://www.apple.com/iphone/easysetup/rateplans.html
Very nice monthly service payment plans! The lowest is $59.99.
Unlimited Stuff!:
Data (Email/Web)
Visual Voicemail
Nights & Weekends
Rollover® Minutes
Unlimited Mobile to Mobile (Wow!)
"All iPhone service plans include Visual Voicemail and unlimited data — Internet and email — so you only have to decide how many minutes and SMS text messages you need. You’ll select your plan when you activate your iPhone using iTunes on your computer."