Straight from the source, Facebook is now at high schools.
Now all high school students can sign-up for Facebook since we are at every high school in the nation. However, these are for high schoolers only, no alumni. Remember you have your own Facebook to play around with.
Here's how to join. Soon, people from your high school and alumni (who are on the college Facebook and are either freshmen or sophomores at college) will be receiving invites. The easiest way to get in is to find a registered member from your school or a registered friend that just graduated and get an invite from them. So unless your from my alma mader, Bridgewater-Raritan High School, I won't be able to give you an invite. (Facebook employees can't break the system that's there.) As an note, each freshman and sophomore college member gets 7 invites.
Finally, the company has a pool going of when we'll hit 1,000,000 high schoolers. I have my money on the 7th. We launched at 12:35PM and currently there are 152 members. So we'll see when that happens. What are you waiting for? Start bugging your friends! Come on Bridgewater, get your asses moving!