Konrand,
Are you looking for a specific solution or just general info? If you're
looking for specific info, could you supply more details about what you want
to do? As a starting point, you might want to checkout the following links:

http://www.microsoft.com/usa/presentations/BuildingCollaborationAppswithSPS.ppt
http://www.tacteam.net/isaserverorg/spskit/1overview/1overview.htm
http://wss.collutions.com/default.aspx (a good site for WSS FAQ's)
http://prade.microsoftemea.com/content/Portals/Sharepoint_Pilot_Guide_Final.doc

Regards,
John