I don't think you're allowed to work or study there. It is difficult to even get a tourist visa. They are extremely strict about who goes into the country. There was a time when any foreigner found there was killed, so I don't think they are keen on foreigners coming to stay.

As far as I know you can only get a tourist visa if you visit as part of an organised group. I would think it would be difficult to work there.

Yeah I was acting in a drama for CCTV and they "suggested" that I leave Tibet while we where filming (but that was right after the 08 riots).

I'm pretty sure you aren't allowed since most foreigners can't go alone and they need to be with a group. If your studying or working it would be a big 'no no' since people who study or work are on their own a lot. That's one of the more isolated places in China. 

No, legally a foreiger is not allowed to work in Tibet, really don;'t know why you would want to study there, there isn't any educational facility worth while in this part of China in less you are studying buddism