I was attempting to connect to a friends test domain across the internet via a PPTP VPN he setup for me. The connection was being made quickly, and I got an IP from the connection, but I couldn't ping anything!
It was a little frustrating until I did a route print. Once I did that I noticed that my default gateway was being reset to the VPN connection IP.
To fix this I went to Network Connections and selected the properties of the VPN connection. Then:
-go to the networking tab
-select tcp/ip and then properties
-click the "Advanced" button
-remove the check mark that says "Use default gateway on remote network"
When I connected the next time the route print looked much better and the connection worked properly and I was able to access both the remote VPN-connected network and it's resources as well as the internet through my local connection. Easy fix, but not totally obvious.