SP2 is not available yet. I have not seen anything anywhere that says when
it will be either. I would hope that Microsoft release SP2 very close to
when they release Vista.
BTW. SQL server 2005 and SQL Express DO run on Vista, but obviously there
may be problems. I have not come across any at the moment. Most of what I do
is purely for my own personal use, and I would think twice about trying to
develop anything serious before SP2 was released. That doesn't mean that it
can not be done.
Graham.