Hey Mark,
Very simple. Without wading thru some tome on the subject, here's an example:

< % @Page Language="C#" ASPCompat="true" %>
< % @Import Namespace="avfpdemo2_dotnetproxy" %>
< %
server x ;
x = new server() ;
try
   {
	Response.Write(x.main());
   }
catch(Exception ex)
   {
       	Response.Write("Caught .NET exception, source: " + ex.Source + " message: " + ex.Message);  
   }

%>

Compile your vfp mtdll and then run tlbimp over it (alternatively, there is some simple setting in vs.net that generates the dll proxy that is called). So, in the above, the proxy dll is declared (which is basically the vfp mtdll), the "server" object is created from the VFP "server" class, and finally the "main" method of the vfp mtdll is called...
>If I create a VFP DLL how can I use it from C# code?
>
>Thanks