Uh... that's not likely to be an issue. You can connect to IRC on dialup easily unless you have a REALLY slow dialup (300baud anyone?).
Routers, firewalls, other internet software... it can all play a part. As you can see from this thread, there are a LOT of causes for connection issues and a LOT of ways to make it work. You really have to troubleshoot it yourself to narrow it down. Otherwise it is just random guess work for anyone to help you and that's not a good way to find a solution.