tcpclient: receiving data asynchronously

Excuse me for all these questions, but I'm still kinda new at this.

I'm trying to write a simple client/client app to send data back and forth between 2 points asynchronously. (sorta like instant message)

I start up 2 copies of the program, and set one to listen for incoming connections. I have the other attempt to connect. They establish the tcpclient and I have the 2 instances send their IDs to each other, with no problem. The problem is that when I have either program send their data, the other one doesnt seem to receive it. I have a subroutine set up to process the incoming data, but i don't know how to make it fire. It's probably something simple I'm overlooking. I can post code if needed.

Thanks again for all the help!!