check ebay for a cheap option - got a feeling they might be known alternatively as V2 Cactus triggers - cheap (similar ones on ebay come under "wireless flash trigger").  But if you want the cream of the crop you need to go no further than a Pocket Wizard. Google/ebay search should bring up both of them...

"In every colour, there's the light.
In every stone sleeps a crystal.
Remember the Shaman, when he used to say:
Man is the dream of the Dolphin"

Rich Meadows Photography