This method, provided you can run the two programs necessary, will enable you to bypass ANY web filter, without the use of any proxy sites that can be blocked. Many people tell you to go to sites like boredatshool.net etc, but these sites can be blocked, which will put you back at square 1.
To prove that this works, these screen images were taken while I was drafting this Instructable to prove that I was using this method from school, where www.instructables.com is a blocked site.
DISCLAIMER: I am NOT responsible for you if you get caught. do this at your own risk.
Step 1: You will need:
the rest of the things you need can be gotten for free.
USB flash drive (if necessary)
mozilla firefox, portable edition
PuTTY, portable edition
shell account with rootshell.be (here it is free)