I found this post this morning, went over there and haven't stopped smiling yet (sad I know). I threw a couple of 10 page or so assignments at it and after uploading a couple of .sty files it all went perfectly and rendered faster than my local machine, which was a bit insulting.

I was a bit taken aback that this has been live since January 2009 (if I'm reading their blog correctly) since an online LaTex editor is something I look out for on a semi regular basis (and has been for years).