Hamachi is great for quick setups and P2P encryption. Created by the folks that run LogMeIn, Hamachi lets you create mini private networks that use unique IPs from a IPv4 unassigned namespace. This is pretty unorthodox, but until some international organization steps in and attempts regulation, there’s a fast free way to get a unique, static IP for free. Hamachi uses this IP to track the various networks in its own server, even though the actual file sharing connection is P2P.

The client installs in a few minutes and can run on Windows, Linux, or OS X, so your VPN network can easily be cross-platform. It’s hands down the simplest, fastest way to set up a VPN out there, though the IP namespace may not be available forever. Did I mention that personal use is free, and commercial use is $5 a month? It’s certainly not an enterprise solution, but for small businesses it’s the way to go, and makes working from home possible. But don’t just take my word for it–read their security whitepaper to get an idea of how their system works before you decide that it’s best for you.