Duke - I recall a few walk-up sports book were closed recently in San Jose because of licsencing problems. I cannot find the thread. I have a link about Costa Rica in general. The thread has lots of info about visiting CR. Maybe someone else will have better info regarding the local walk-up sportsbooks.
When you get there to the airport, I suggest picking up a copy of the Tico Times newspaper. There are ad's in it from local casinos and some of them do mention having sportsbooks.
El jefe and the rest,
There are no walk-in sportsbooks available right now in any casino that I know of in the San Jose or surrounding area. I live here and I can attest to that.
When I was there, there were lots of walk up sportsbooks, but it has been a while, I would get some of the locals in this thread to answer this question.
The walk-in books were crap anyways, weird limits and terrible numbers. You would be better off just logging in daily and making your picks as there are internet places on virtually every block. An hour of internet time in most places costs about a buck.