I currently have a small application that serves as a peer-to-peer file 
transfer program that uses XML web services on a central server to 
connect to other users.

My question is, say if I had 2 users both behind residential gateways, 
how could I send a file/msg between them?

I'm using VS.Net 2003 to develop this in VB.Net.

Any help/comments/suggestions would be much appreciated thanks in advance.

Chris