we have an old server that we want to dedicate fully as a public webserver (hosting a few DotNetNuke sites), and for this purpose we would like to install SQL Server Express (probably 2008) on the server and thus have both the Database server and the Web Server on the machine.
But: The databases for the webserver are hosted on a SQL Server 2005 Standard today.
So the question is: Is it possible to move a database from a Standard Server to an Express Server?
Answer: yes. It is possible. It is actually trivially simple (detach database, attach at new server instance).
Btw., take 2008 R2 express, not 2008 express. 2008 is outdated already.