Custom webpart development using ASP .NET.

There are many references found on the web for custom webpart development, some of which I am adding here, if you want any specific functinality then let me know.

http://www.codeguru.com/csharp/.net/net_asp/webforms/article.php/c12293/

http://www.datasprings.com/Resources/ArticlesInformation/Sharepoint2007CustomWebParts/tabid/775/language/en-US/Default.aspx

http://msdn.microsoft.com/en-us/library/ms452873.aspx

Hope this helps!!

Thanks.