I've been trying for days to get my VPN to work and haven't had
success.  I will describe the setup in as much detail as possible.

One network is behind a Linksys WRTG54GS wireless router (all computer
are connected by wire).  I have several computers running XP Pro and
one running 2003 server.  I set up the 2003 box to accept VPN
connections and forwarded the vpn port.  I also have 2 network cards in
the 2003 box, both connected to the router.  I set up Routing and
Remote Access on the 2003 box (VPN and NAT) with one NIC for the local
network and one for the VPN.

The other network is also behind a Linksys router (not sure of the
model # but it is not a VPN router).  There are also several XP Pro
machines and a 2003 server machine.  I tried to make a VPN connection
from this network to my other network.  I can see the session on the
2003 box, but i can't see the computer on the network, nor can the
other computer see anything on my network.

Are you setting up a L2TP, an IPsec or a PPTP VPN ?

Useally with windows, the default VPN ares L2TP + IPsec, then PPTP if
the L2TP + IPsec VPN cannot be opened.