as an owner of the source code license, you will get the text chat module for free. At this point, it requires a couple of hours worth of work on integration with custom projects, and we will provide you with instructions.
Chat module looks and works similar to the Facebook instant messenger - it allows you to pick a user from the list of your friends/contacts and send him a message in real time. The other side gets the instant notification each time a message is entered.
I will send more details via e-mail.