onias, I'd check to make sure your wireless router doesn't have a built-in firewall. I had that same problem- I was opening the ports on the DSL router, but didn't realize that there was another one on my wireless network router that had to be dealt with as well.
Anyway, now I have a little problem of my own. Last night mIRC just stopped being able to connect to any server. I just keep getting the "Unable to connect to server" error over and over. I can connect just fine with x-chat and a java client, but not mIRC. I've tried getting the latest version of mIRC, but no dice. I've tried connecting to a server with the IP rather than hostname, but still no luck. The only difference that I can discern between now and yesterday, when it worked, is that my IP seems to have changed. Any ideas what could have caused this?