If you're in school, though, then it's even worse. No matter what country you're in, chances are that your access to the internets is as snooped-on as any police state in the world.
So, how do we escape our little virtual prisons? In this Instructable, I'll tell you about something called Tor (The Onion Router.) I'll tell you how it works, and then offer some simple instructions on how to get your web browser hooked up. No more getting snooped!
Step 1: How Tor Works
Tor works because the school has a finite blacklist of naughty addresses we aren’t to visit, and the addresses of the nodes change all the time—no way could the school keep track of them all.
There's a more complete overview, here, but let's get on to installing Tor.
Step 2: Install Tor
A screenshot of the installed Vidalia app on OS X is below. The window shows that Tor is up and running, ready protect me!
Next, we have to set up the internet program I use the most: my web browser.
Step 3: Set Up Your Web Browser With Tor
Setting up TOR with Firefox is also really easy, since there's a ready-made add-on for Firefox: Torbutton. Just go to this link to download the add-on, install it, and restart Firefox to get it running.
When it's installed right, you'll see a link at the bottom right of your browser window, reading "Tor Disabled." Just click that and it will switch to "Tor Enabled." A series of screenshots are below to help you out.
Once it's running, you're protected! All of your data will be running from computer to computer and switching paths, hiding your location. Web pages will load a little more slowly because of this, but when you need to get online safely, that's a small price to pay.
BTW, when I say you're protected, I mean that you're mostly protected. Read on; my last step talks about other things you can do to improve your security even more.
Step 4: Now, Be Careful
The first thing to do is to remember always to enable Tor when you're online. Maybe you want to maintain a profile on a site somewhere (like Instructables!) that no one can trace to you. If you forget and log in just once without Tor enabled, your real location will be recorded in the logs. So, be careful!
Second, you can start Tor-ifying your other internet apps: IM clients, email, etc. There's more information about this here on the Tor wiki.
Computer security is a constant arms race. There are smart people all over the world (criminals, government snoops, not to mention ADULTS at your school) who are always trying to see what you're up to or block where you want to go. No security is perfect, and they'll find ways to chip away at your defenses.
Good luck, out there.