Sharepoint Web Parts and ASP.Net

Just started working with Sharepoint last week, so excuse me if I am stating an obvious question.

We are working to develop some web parts (some are connected) for Sharepoint, but we believe we are going to want the same functions to use outside of Sharepoint.

What is the best way to develop web parts to be deployed on Sharepoint but then also be able to use the objects for other development?

Thanks in Advance