Save time and buy a VPS or install Debian in a virtual machine.
Using a SSH Tunnel you can view all content unlike most PHP Proxies (To be honest they suck)
FTP and SQL DBs won't help you at all.
So install Debian
Download Putty Tray
to connect to YOUR OWN IP
, not mine.
Create a new SSH Tunnel
in the settings. Selecting a dynamic
Save and login to your host.
Open FireFox -> Tools -> Options -> Advanced -> Network -> Settings
There you go, you've bypassed school firewalls.