Hmm... I wasn't out at school (oh boy... was THAT a lifetime ago!

). I do know about harassment though.
I was different enough to get people screaming "freak" at me, being spat on, shoved, knocking my lunch out of my hand, being told to "watch your back", and some... err... "interesting" things written in the toilets about me and a certain inclination to do things with androids (That were supposed to be insulting... but I just found them rather funny).
It tapered off by about grade 10 (except the android thing... no matter how many times I denied it

).
You learn to deal with it. School isn't the be all and end all of life it appears to be from the inside. Once you're finished there, you'll probably never speak to those people again.
Ignoring people is all well and good - but they'll just keep going until they get a reaction, and people are going to think you're sooking.
I found it was best to give them a reaction, but give them something that says you don't care what they think. Cynical is good. Angry or upset will just egg them on.
A deadpan responce of 'Wow... that was mature", "Uh huh... whatever", "Are you finished yet?", "Try harder next time", "(laughing) Wow... it's true. You ARE a complete tool!" and things along those lines worked well for me. You've just got to get the inflections right and you're set. If I was feeling lazy, I'd just look at them blankly for 2 - 3 seconds with raised eyebrow and go back to whatever I was doing.
Kids pick on what they percieve as weakness. Stand tall and be proud of who you are, and eventually they'll figure out that your difference is not a weakness and leave it alone.
Having a chat to the teachers before class is a good idea. Show up early during the first few days back and try to hit up the staff rooms before school starts. Teachers don't like having to stop class / delay class to have talks with students, so this might be a better way to go about it.