How can we quick look at our contacts and see how is having iMessage or not? So we can easily contact them, instead of going through all contacts one by one to check them.
The feature you are looking for does not exist in iOS 5.0. I guess the reasoning is that you just want to send a message to your contacts and the device will send it via the appropriate route, favouring iMessage where it is available.
The closest you can get to seeing who has iMessage available without visiting each contact's card individually is if you go to send a new message, type 'a' in the
Other that that, when you're sending a message...
If the Contact's Name and the Send button are green, then they don't have iMessage available and you'll send them an SMS (or MMS).
If the Contact's Name and the Send button are blue, then they do have iMessage available and you'll use that.
I have been searching for a month but didn't find any method any trick not any 3rd party app or not even a Cydia tweak to identify all my iMessage users & the point of hitting compose new and add a user to check if it turns green or blue.
In short there's no way you can find it so don't waste your precious time for searching.