From VNN Networks:
A simple to use and easy to setup VPN. A Plug & Play VPN service. On-Demand VPN service. No need for a fixed public IP address. Create a VPN in less than 5 minutes. Access home and office PC from anywhere. Extends LAN based business applications over the Internet. Connection multiple offices securely. Allow remote support engineers to access the enterprise servers. Remtoe troubleshooting a remote employee's PC. Support IP-Camera, SOHO NAS.
Works without problems after you detected how to apply it. I use it with windows 2000 and windows Xp, assigning drive letter over the internet, starting e.g. installations from the remote disk by double clicking the package. Also used in in combination with XP remote desktop and RealVNC. Ideal for connecting a number of (workgroup based) small offices together or connecting all family PCs in different locations together.
A disadvantage compared to VPN is that it connects computers peer to peer instead of extending the LAN giving access to all shared resources on the LAN. But I expect it will give access to all shared resources known by the computer you connect to.
All documentation is on the web pages but not always easy to find.