I wish this service was available for Mac clients!  Probably the easiest way to do VPN.  From its webpage “Gbridge is a free software that lets you remotely control PCs, sync folders, share files, and chat securely and easily. An extension of Google’s gtalk service, Gbridge automatically forms a collaborative, encrypted VPN (Virtual Private Network) that connects your computers and your friends’ computers directly and securely. Gbridge has many unique features.”

It should be stated this is not a Google service.  The company claims that they don’t have access to your username/password since it is encrypted.  If you have security concerns you could create a second google username/password just for this service but your first account information is not linked to it.