OpenVPN is a robust and highly flexible tunneling application that uses all of the encryption, authentication, and certification features of the OpenSSL library to securely tunnel IP networks over a single TCP/UDP port.
I had to install this software to support a customer. It slowed my Win7 box down significantly, so when I was done, I went to remove it. Almost any time someone tells you you have to run software with administrator privileges, it indicates lazy or just plain bad coding. (see the directions on their website for use with Win7.) This software refused to let me remove it, even as an administrator. It deleted my user and group rights off of the different files it installed; it blocked me from even loading regedit. I booted into safe mode, manually removed the registry entries using regedit, and I deleted all the files. On reload, all the files I had deleted had been recovered and reinstalled. However the registry changes all held, so after another round of file deletes, it appears to be off of my system. Horrible software. I will not be letting anyone I know use this. I'd suggest checking out ShrewSoft VPN. It is a pain to get working, but it doesn't slow your system down, has better features, and it lets you remove it cleanly if you need to.