Unlimited texting for iPhone to iPhone users

[hypo]

Update to new iOS 5, but when you do one of the features only works if you identify your contact as owning an iPhone.

Unlimited free text messages/MMS among iPhone users requires you to identify your contacts that have iPhones and when you send them a message it changes from text message to imessage and the color of the message changes from green to blue.

JUST an FYI to help save a buck if you don't already a have an unlimited texting plan.

I have these people as using iPhones:
Jeff
Missy
Clayson
Serban
Becky
Doug