This is a bit of a cross-post, but I found it really hard to find any Mac OS-X info when I was searching earlier, so I thought this post may help others.
First - for those looking to USB-to-Serial Adapter Cable working in OS-X, you need the VCP driver from the FTDI website here: ftdichip.com/Drivers/VCP.htm
The driver linked from the LynxMotion page (as of xmas '09) is for Windows only and, of course, won’t work. You need the VCP driver to get the /dev/tty mount.
Once you have that, you can connect to the SSC-32 via a terminal program like zterm. Issuing a "ver’ command will let you know the SSC is responding. Make sure to turn on local echo.
I also wrote a little console application to play with the arm. You can read about it in my other post here: viewtopic.php?f=6&t=5766
Anyways - I hope this helps someone!
-Scott