+1 for inkista (as usual!).
If you want off camera TTL, you are narrowing down your potential options (and also increasing the price). You will need a transmitter unit for your camera (sits in the hotshoe) and a receiver unit for each flash you want to use off camera. The nice thing is that if you only plan on using one flash, TTL transmitters are sold in pairs (transmitter/receiver), so you don't have to worry about buying multiple items to start out.
I personally have the Pixel Kings and use them with both a 60D and 5dm2 in combination with a 430exii. Pocket wizards are the brand known for reliability, but I've had great results with the PK's.
With all of this said, I don't use them nearly as much as I do my manual triggers.
Olympus OM-D/Panasonic G3