I'm sure most (all?) IRC clients and servers can be configured to use port 8080 if you want to. If the server runs at 6667, but you need to use port 8080 because of a firewall - then you need to have another machine *outside* the firewall that can "convert" port 8080 to 6667 (i.e. you connect to that machine:8080, which in turn connects to the IRC server on port 6667).