How to setup a VPN server from a home network with an Ubuntu server

view story

http://askubuntu.com – So here is what I want to do: Set an Ubuntu Desktop box as a media center for my TV. Use the same box as a local network storage. Need to have VPN access to the same box from other outside computers. The media center part is simple enough. The rest is where I'm having trouble. Here is the local network setup I have in place: I get DSL Internet from a Speedtouch modem (fixed IP) with DHCP setup. Internet goes via cable to a Cisco e1000 wireless router set as a regular switch. Further on there is a cable connection from the e1000 to my Windows 7 desktop. Then there is the ubuntu desktop b (HowTos)