Hey,
It should be a reasonably simple matter to get the Club Site to run under SQL Server 2008, it should just be a matter of changing the connection string for the database.
The best place to find the correct connection string would be here:
http://www.connectionstrings.com/
Obviously, you will need to move the database into the SQL Server instance.
A slightly more long winded way, if you really wanted to use XML would be to implement a true n-tier database access layer, and then implement a provider for the XML file that you wanted to use. For a very good example of an n-Tier approach, I would suggest you have a look at the BeerHouse Sample Kit, which you can find here:
http://www.asp.net/downloads/starter-kits/the-beer-house/
Hope that helps!!
Gary