getting my mac to work with an ISA proxy server

i can use safari and msn messenger fine just setting the web proxy to the address given to me by my school admin 192.168.0.3 with the port number 8081 that works great but my admin has told me that there is no mac proxy client so i cant use other services like ichat and IRC, he told me to try using SOCKS but ti dosen't work, any ideas?