WSS 3.0 Automatic Logoff

After upgrading a customer from SBS 2003 to SBS 2008 we had a problem with WSS 3.0 automatically logging users off after a period of inactivity.

This is remedied by:
-SharePoint Central Admin
-Application Management
-Web Application General Settings
-Web Page Security Validation
--Set the timeout to a period that you like - or just set it to 'never'