Use This No Matter What!!! It blocks Anti P2P IP Address Ranges, School Trackers, Government Intrusions... Etc.
Peer Guardian 2 (Not set for Vista YET! Use on XP Only)
http://en.wikipedia.org/wiki/Peer_guardian_2
You will have to disable it to access your school's systems but that is easy to do...
Hotspot Sheild
http://www.hotspotshield.com/
Vidalia (A B*TCH to get to work...)
http://vidalia-project.net/
THOSE are free but for pay you can get:
Anonymizer
http://www.Anonymizer.com
Then you check to see if your proxy of choice is working, go to:
http://www.whatismyipaddress.com