Tunnelblick is a free, open source graphic user interface for OpenVPN on OS X. It provides easy control of OpenVPN client and/or server connections. It comes as a ready-to-use application with all necessary binaries and drivers (including OpenVPN, easy-rsa, and tun/tap drivers). No additional installation is necessary -- just add your configuration and encryption information.
Support is provided by the Tunnelblick Discussion Group.