For those of you on AT&T, on one of their nationwide calling plans, and have the unlimited messaging plan you can get free mobile to mobile calling to any cell phone (regardless of carrier) starting today. Basically you replace your unlimited messaging plan with the unlimited with mobile to any mobile calling plan which are the exact same price.
Sprint has this feature which I really enjoy since almost all my calls are to other mobile numbers and thus I never actually use any minutes.
It seems AT&T is feeling a bit of pressure after losing the exclusive rights to the iPhone. Competition is good, although I’m unsure of why AT&T couldn’t just toss this upgrade on automatically instead of making you manually switch it (and not apparently advertising it to any great extent).