User Controls and Sharepoint

http://www.sharepointblogs.com/zimmer/archive/2008/01/10/moss-2007-using-ajax-usercontrols-in-sharepoint.aspx

http://www.codeproject.com/KB/sharepoint/WebParticles.aspx

http://www.intranetjournal.com/articles/200601/ij_01_20_06b.html

http://bloggingabout.net/blogs/mglaser/archive/2006/10/06/Using-dynamically-loaded-User-Controls-in-SharePoint-2007-_2F00_-ASP.NET-2.0-Portals.aspx

http://blogs.msdn.com/cjohnson/archive/2007/03/28/using-asp-net-user-controls-in-your-wssv3-moss-aspx-pages.aspx

http://fusioncs.blogspot.com/2007/03/using-user-controls-in-sharepoint-200x.html