I haven't, but another thing you could do is use a PIC microcontroller to drive a transistor via Pulse Width Modulation to provide dimming as well. A bonus is that it's fairly easy to get it to communicate with a PC via RS232.Originally Posted by NiteMax Mark
For under $20, you could get an 18pin Olimex protoboard that has everything (voltage regulator, comm port, max232, 20mhz crystal, etc) all wired up and ready to program. Just need to run TX/RX to the MAX232 and the hardware is done. PWM is easy to generate in software or just get a pic that has a CCP module and it can generate the PWM signals for you.
If you went with the 16F877A and a 40-pin board, you'd get eight levels of ADC too and 32 IO pins overall. Plus two CCP modules.
You need a programmer too, but they can be had for as cheap as $10.
If you're not an assembler guy, you can use Hi-Tech C's free version (PIC Lite), just make sure you get a PIC that's supported in the free version.