WatchGaurd Firewall

I am looking for a way to get Some spcific programs to work on this network such as, for example Limewire or E-Mule…or online games like say Halo for PC. Web browsers work…I am certain that it is a problem of what ports I use but unfortantly I have very little knolage on these things, I know that there are port scanners that tell what ports are open, but again this is not my area.