Where's the designer surface?

I've seen a lot of tutorials about creating Web Custom Controls in which after adding a control to the project i VS.NET, you get a design surface that you can drag controls onto. When I'm doing the same in VS.NET 2003 (C#), it only gives my a class file and I can't find any way to see or add the design surface. Does anybody know if or what I'm doing wrong ? Thanks in advance Thomas