How long are you leaving it idle?
if it's just until the new year, you don't have to worry _that_ much. If it's for a whole year, I'd try to arrange to have someone come along and start it once every now and then, and move it, so the brakes are not binding. Best of all, if you can get it run around by someone _reliable_ once every month or so.
Trouble with that, you might find the person takes it as an invitation to have a free bike for their use indefinitely - some bastard did that to me years ago. They asked if they could use it for some specific need, sure I said, next thing I heard, they were using it every day and calling it their own.
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Anyway - grease every joint, drip oil down every cable. Vaseline all the hoses and anything rubber, it'll stop it cracking and drying. Make sure you get all the crap off it first, and apply decent polish (auto-glym or whatever), and I might be inclined to get it supported on the frame, not the tyres, or you'll get the tyres squared off in places. And maybe flat-spots on the wheel bearings.
Definitely disconnect the battery, remove it from the bike, in fact. The old oil won't expire if you changed it on Sunday. Don't drain the tank, but don't leave much in it. Metal covered in polish/oil etc. won't rust. That's all I can think of for now, the others will have better ideas, I'm sure.
Good luck at Uni.
