Sharing internet w/ DHCP off

[yg17]

Last year in my dorm, I had my powermac connected to the ethernet in the dorms, and then shared out internet over airport so I could use it on my iBook and it worked great. This year, I've been reluctant to do so because IT has been cracking down on people running DHCP servers (why, I dunno) and a friend of mine got banned from the network for 2 days for doing the same on Windows. Is there a way to allow me to set up sharing like this without using DHCP, maybe allow the PM to act as an access point and give the laptop a school network IP? Thanks