The easiest way to do this is to use a library called pcap (or winpcap for Windows). There is a program called Ethereal which uses pcap to monitor port traffic. Ethereal is free, and works very well.
Is it possible to just listen to that port for incoming and out going data?
This is much harder to do. It would be far easier to code an IRC bot from scratch than to learn how to inject TCP packets.
Also, Is it possible to inject data into the TCP stream?
What's the problem then? If you know the IRC protocol and you know a programming language, then start coding!
I know the protocol (IRC) protocol. My problem is I have a IRC bot for my IRC room and well, it be much easier if I could just program the bot in a language I like and know.
This doesn't make sense. How can your computer or network be set up to disallow multiple IRC connections?
Also, I could just program the client in one language, but my computer and network is setup so It creates problems if I have mutliple connections to IRC.