easiest way would be to make your pc the router. it would need TWO network cards and would run best if you could install win2k on it, but you could also use ICS in win98.
basically, the ethernet would come out of the wall and into NIC #1 in your pc, then NIC #2 would have a crossover cable going to the NIC in your laptop. then you'd configure NIC #1 for your college network, enable ICS, and then proceed to setup your laptop to route through your pc.
there's obviously details i'm leaving out, which i don't have time to go step-by-step through now. but if you search around the networking forum, you can definitely find others who are doing the same thing.
btw...MANY colleges do not allow multiple pc's to share one ethernet port. granted, lots of kids do it, but just remember that you could lose your backbone connection if it's illegal and you're caught.