I picked one up from Zen Racing. I actually back ordered mine and asked them to send it with two transponders and Zen got ordered and delivered with no issues to the US.

I'm using android with the Timing Beam App on a Galaxy S2. It was super easy to get working except that I can't get the spoken lap times to work. It will announce the race start and timer, the welcome message, etc. but not the lap times. I've checked and unchecked the button for them with no change. I also tried both the google and samsung speach engines, adjusted the speach speed, and every other adjustment that I could find but it just won't speak lap times.

Any ideas?