VPN Using WIN XP AND DLINK 504 ROUTER

Hello,
Can anyone please help me setup a VPN using Windows XP with a D-Link 504 DSL/SWITCH/ROUTER.

I want to be able to set it up to act as the server to accept incoming.
What ports do I need to redirect, what IP do I use?
I would really appreciate some help, if someone has the time and patience to explain it in easy to understand language, or point me to some easy to read tutorials that deal with router configurations and XP.

Thank you