I got a question from Amit Vasu regarding the installation of SharePoint Portal Server 2003 with SQL Server versus MSDE. The issue was that his customer first wanted to use MSDE and if needed later on migrating to SQL Server.

This is possible and i did some investigation on MSDN and found the following. There is an article describing the migration from WMSDE to SQL Server:

http://www.microsoft.com/resources/documentation/wss/2/all/adminguide/en-us/stsf17.mspx

After this you have to change the connections in SharePoint Administration of the databases. the following walkthrough describes it:

Open the SharePoint Central Administration website and go to the "Windows SharePoint Services Central Administration". You will find under "Server Configuration" the option "Set configuration database server". Here you can change the configuration database to its new location.

Go to the "SharePoint Portal Server Central Administration". You will find under "Server Configuration" the option "Configure server topology". Here you change the content, component settings and configuration database to their new location.