All you need is a is 2 Linksys VPN routers or a 1 VPN Router and SSH Sentinel. Do a google search or check the Linksys Knowledge base and read up on it. It fairly easy once you educate yourself first.

Window XP Pro also has some VPN capabilities but I have not heard many good things about it.

For a very easy solution and much faster check out www.gotomypc.com .

Search VPN on this forum and like most other things on this forum some very smart people have addressed the subject.