LogMeIn 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. It works with your existing firewall, and requires no additional configuration.
Hamachi is the first networking application to deliver an unprecedented level of direct peer-to-peer connectivity. It is simple, secure, and cost-effective. Hamachi is currently available for Windows 2000, XP, 2003, and Vista. Console versions of Hamachi are also available for Linux and OS X.

· No hardware required – A quick, simple and easy-to-use VPN that just works
· Secure communications – Encrypted tunneling across public and private networks
· Flexible networking – Combines the ease of an SSL VPN with the connectivity of an IP-sec VPN
· Web-based management – Deploy to anyone, manage from anywhere, access anytime
· Free for non-commercial usage – Absolutely free for non-commercial use

Download: LogMeIn Hamachi 2.1.0.159 (3.7 MB) | Screenshots | Homepage