Yeah, if you get suspended from a public school for anything on you post on myspace and/or other webpages (aside from personal threats/bomb threats, etc) it is a HUGE violation of your first amendment rights.
I would tell any kids you know that have been suspended for this to file a lawsuit, some kid in Ohio recently settled for $30,000 because he was suspended over comments he posted on his website. I really hope schools get fucked over by this and learn, it's definitely very illegal.
http://www.freedomforum.org/templates/document.asp?documentID=9492