Version 1.4b3 added preliminary support for Mac OS X (use the Carbon version). This version has only been "lightly" tested on Mac OS X, and has known cosmetic bugs.
Version 1.4b2 added support for controlling (connecting/disconnecting) a PPPoE connection.
Carbon (For Mac OS X and Mac OS 9 with Carbon libraries)
Source code for a Unix command-line utility. (Only tested on FreeBSD, but should work on Mac OS X, Linux, etc.) (Also available as Binhex'ed self-extracting archive.)