The good news is that there are ways to work around the internet filters and access blocked sites anyway.
The easiest way to get access to a blocked website at school is to use a proxy. You can access any other blocked site this way as well.
It's good to use a proxy site that hardly anyone knows about. Proxies that get used a lot will get discovered and blocked sooner. Proxies that you find by searching Google will be blocked quickly because they're so easy to find. Even if you get a good proxy it's a good idea to have a few others you can use if it gets blocked.
An alternative method of unblocking websites at school is to set up your own proxy tool. This is more advanced than using someone else's proxy but it's a lot nicer to have because you're in control. Explaining how to do this is beyond the scope of this article, if you do a search for "How to make your own proxy" you should find help. You can even make some money from letting people use it through advertising.
Other ways to get on blocked websites include to use sites that translate pages, such as Google Translate or Babelfish. Also try Google's cached copy of the site. Unfortunately, it's not possible to log in that way, so it's still best to use proxies for Myspace and Facebook, though these tips are great for many other sites.