Thanks to David for reminding me about Yongnuo's new RF603 Wireless Flash Triggers. The new RF603 version (replacing RF602) is both a transmitter and a receiver hence the name 'transceiver', so you can use each one as both. The old RF602 version required both a separate transmitter and reciever unit in order to work. There's a few more new features that make the RF603's a better buy if you don't already own a set, but a bit of bad news is that they are 'not' compatible with the older RF602's. Blah. I have quite a few of the RF602's.
One thing that might be confusing if you're looking at the product pages would be the difference between Canon and Nikon versions. The units are all the same and the difference is the provided shutter cable. The RF603 Transceivers can also act as a remote and receiver to fire your Camera's shutter wirelessly (sorry no video starting). You can find out more information about Yongnuo's RF603 following the link.