In VS 2005 create your project and then just add new items whether they be VB.NET, C#, etc items
I would argue that the app would be more difficult to maintain with a combination of languages, and staying with one would be a better choice.
HTH
Would you know if this option is available in VS 2003?
I completely agree that a combo of languages is probably not the best way to develop. I'm simply looking at all of the new and exciting things that .NET has to offer.
Thanks for your reply!