Putting a new site or just an upgrade of an old site in IIS is pretty easy. You just have to go to the ASP.NET tab of the site configuration and select the version (2.0....) you need. I found a quick Blog entry on this.
Something I am noticing though is that is causes my web server to stop. I get the following error:
Failed while restarting W3SVC. Error code: 0x8007041d
I have to mannually run iisrestart to get things going again. Anyone who has a clue, please post your solution as a comment.