Use External Database with SharePoint

http://grounding.co.za/blogs/neil/archive/2007/12/17/connecting-an-external-database-to-sharepoint-using-the-bdc.aspx

http://social.msdn.microsoft.com/Forums/en-US/sharepointdevelopment/thread/e3d7a890-8421-47c8-90e8-937c057f054c/

http://joeshepherd.spaces.live.com/Blog/cns!9AE2097A4A610B63!127.entry

http://www.codeplex.com/threetierwss/Release/ProjectReleases.aspx?ReleaseId=2856