setting up a VPN

I need to set up a VPN. We have 3 sites in the area that need to have access to 1 database.

I have running windows 2000 server and have a ADSL with a dynamic IP address. We use a Dlink ADSL router to connect to the web.

I have tryed to setupa VPN but cant get a connection.

PLEASE HELP

if you require more information please do not hesitate to contact me