Adafruit MiniPOV 3 Kit
Adafruit Product Code: 20
This kit can definitely be used with a USB serial port converter on MacOSX/Win/Linux but I can't guarantee it will work with just any converter you use. It has been tested to work with the USB/Serial adapter in the shop and other PL2303 and FTDI-based adapters.
If you're using a MacOS X and a "Prolific PL2303" chipset USB converter you should download and install the PL2303 OSX driver available here instead of the one on the CD.
Don't forget to read the instructions over at ladyada.net!