iMessage

Since I upgraded my iPod to iOS6, I haven't been able to use iMessage. It won't send messages to any of my already established contacts. I've read similar comments on other Internet sites. Any help in getting it to work again? Already reset my network connection as one site suggested. Didn't work.
Thanks for any help you've got to offer.

Settings > Messages > iMessage [ON]

It should go without saying, but since you didn't mention it -- iMessage only works between other Macs and iOS devices that have either OS X Mountain Lion (10.8) or later, or iOS 5.1 or later. And of course only if all parties have elected to turn it on (it should be on by default on most devices, but users often aren't sure what they are doing and may deactivate it).