Two things to do are set up an SSH Tunnel from home to school using putty or you can use a portable browser on your memory stick. My school is so stupid, the use a proxy to filter, I put firefox portable on my memorystick and away i go. BE CAREFUL THOUGH! Luckily my teachers are nice so they said Cool, can you show me (teachers get blocked too!). If it breches your schools Computer Agreement BE CAREFUL or DONT DO IT!
Firefox Portable
Thunder bird Portable
Miranda IM Portable
Opera Portable