A month ago I wrote:
I don't know if anyone here has played with Hamchi: www.hamachi.cc
Nobody replied on this, so I'm not sure if that's lack of knowledge or lack of interest, but in case it's not the latter there does now seem to an early Linux client for Hamachi (you need to register on the forums and ask for it at this stage, but it proves that it is being progressed). My attempts at installing it have been 100% successful, which is nice.
It's still closed source, of-course, but I don't know of any OSS alternatives (I daresay they'll come if Hamachi proves useful).
Mark Rogers, More Solutions Ltd