The best way of getting on Myspace at school is to use an unblocker. You can access all other blocked sites this way. You can find links to unblockers at the end of this page.
What is an unblocker?
An unblocker is like a gateway that pass information between your computer and the site you want to go to. The unblocker accesses the site you want in your place, accesses the page, and sends it on to you. So the site you want to access only sees the unblocker's IP. So in effect you are visiting sites in an indirect manner. School firewalls only see you visiting the unblocker, not the destination site.Some advice for using unblockers for Myspace
It's good to use an unblocking site that isn't well-known. This is because popular unblockers will be found and blocked by the school. Unblockers that you find by searching the internet will get blocked more quickly because they're so easy to find. Even if you get a good unblocker it's always wise to have a backup you can use if it gets blocked.An alternative way to unblock Myspace at school is to set up your own unblocker tool. This is more complicated than just using an unblocker but it pays off because you can make more of them. Explaining how to do this is not in this guide, do a search for "How to make your own proxy" you should find instructions. You can even make money from this if you put ads on it.
Other ways to access Myspace are to use translator sites, such as Google Translate or Babelfish. You can also try using Google's cache copy of the site. Unfortunately, you probably won't be able to to log in that way, so it's still best to use unblockers for Myspace, however these tricks work with most other sites.
More info: Unblock Myspace at school