How about some flyers in local libraries? Plenty of students gather there to study and might be glad an additional resource. If you talk nicely to the librarian you might be allowed to add a pile.

The handy thing about there too is a lot of libraries offer internet access, so it'd be easy for a student or parent to pick one up and go check out your site there and then.

If you have an internet cafe close at hand, that might be another option for placement.