To easily develop complex webpart’s interface, you must use SmartPart.

SmartPart let you create ASP.NET UserControls and use it as SmartPart with easy deployment.

SmartPart is dedicated to ASP.NET 1.1 projects and all versions of Sharepoint 2003.
Son of smartPart must be used with new Visual Studio 2005 controls (Webparts..) with WSS 2003 SP2 and .NET 2.0

Download it to : SmartPart