LogMeIn's Hamachi is "a VPN service that easily sets up in 10 minutes, and enables secure remote access to your business network, anywhere there's an Internet connection." This is the easiest way to create a VPN network between computers and networks. If you have tried setting up PPTP or IPsec on Linux, you'd know what I mean when I say "easy".
Hamachi is popular with Windows users because of its easy GUI interface. Although it supports Mac OS X and Linux as well but both do not have (yet) the full GUI Windows users enjoy. If you wish to use Hamachi on Linux, here's a HowToForge article on how to install it on Fedora.
Incidentally, the community took it into their hands to create their own GUI front-end for Hamachi on Linux. You can check them out at Hamachi-GUI, YAHG and Quamachi.
To me, even if they say it is 10-minute easy, I'd rather setup a VPN service that is standards compliant.
[image from LogMeIn's site]
*-*Your site is very good. There are useful information and most importantly, for sharing great. Thank you
Also make sure you check out http://computarz.blogspot.com/2010/06/updated-hamachi-keep-alive-script.html
It’s a script I run with cron every 5 minutes and it checks if hamachi is running and kills it and restarts if necessary. Basically it keeps hamachi alive and kicking. And more importantly it tries to keep all the hosts connected all the time.