[DotNetDevelopment] .NET Framework Forward Compatibility

[Tom]

I am developing applications using Visual Studio 2008, which uses .NET
Framework 3.5.  Some of the people that I want to use the application
have previous versions of the .NETFramework.  Assuming that none of
the classes I use are specific to 3.5, is there a way I can build the
application so that it can run with previous versions of the framework?