how do I know if a message I receive is via txt or iMessage?
Using Messaging/iMessage on an iPhone 4 with iOS 5 and I already know that if I send an iMessage, I will know it sent via iMessage because the message bubble will be blue. However, how do I know if a message I receive is via iMessage? All received messages seem to be grey. This is important because I have a very limited txting plan. Thanks!