I've got a theory about the lack of student scholarship / ticket options for WWDC 2008 (thus far).

I think Apple is expecting so many new attendees for the event because of the iPhone SDK that they aren't sure there will be enough room. When you're running out of room and prioritizing, it's not hard to understand that free and cheap tickets are the last to be offered. I'm guessing they're looking at ticket sale trends and figuring out where they'll be by June. Chances are they won't have room to accomodate students this year.

If they're going to offer student scholarships, they'll need to get that process underway soon so that students can apply, find out if they're going and make travel arrangements.

The other theory... last year, students were mistreated during the keynote, they weren't allowed into the keynote because there were too many attendees, and worse yet they weren't brought into the auxilliary room until the keynote had already started. We were literally held in a corner until they were ready to let us upstairs. Quite a few people complained about the poor treatment, so maybe they just want to avoid issues like this by simply not having the students there.