I would recommend going. The experience is great, and as I've said before, I feel that ASA's interview is one of the harder interviews in the regionals, and just experiencing it is worth paying for a hotel.
On another note...as I understand it there was a class on 3/31/08, and ASA started pooling around 3/17(?) and now there is a class on 5/5...I'm wondering if the 5/5 class is really full, or if they just haven't notified everyone yet. Has anyone who interviewed after 3/17/08 been notified about being apart of the 5/5 class?