Q) For the SQL Server 2005 training, should we use SQL Server Standard or SQL Server Enterprise?
There are a few differences between what's available in each version of SQL Server 2005. You can find a nice comparision at:
Q) Can we run SQL Server under both Windows XP and Windows Server 2003?
The Enterprise edition of SQL Server 2005 requires Windows Server (2000, 2003 or 2003 R2). However, you can run the Standard or Developer edition on Windows XP.
Q) If we're planning to use virtual environments, should we use Virtual PC or Virtual Server?
Both Virtual PC 2004 and Virtual Server 2005 R2 will work. They are both now available as a free download. You can find details and differences at: