Things to take care before installing SQL Server 2005 on Vista operating system or Windows Server 2008?
I have seen mounting questions asking on support for SQL Server 2005 on Vista & Windows 2008, what a surprise!
As Windows Server 2008 (aka Longhorn) is still in CTP (BETA 3) stages it is hard to comment or confirm any sort of support arrangements from CSS, also Microsoft strongly recommends to use this combination for testing purpose only. Then coming to Vista there are few things to you need to take care and for further information refer to SSPFAQ post.