[RESOLVED] Dumb DLL Question

I'm having a major brain fart so I need a little help. I have a windows application that I want to use as a class library. Stated another way: I have an executable that I now want to save as a DLL for use with another program. How do I convert the .exe to a .dll?

change it in the project properties

Thanks

I knew it was something simple that I was over looking. I think that my brain has already left for the weekend.