Keep it simple. Try the Cowboy Studio NPT-04 4 Channel Wireless Trigger for External Speedlites:
http//www.cowboystudio.com/product/c14/p140704-11.php
Amazon also carries this product:
http://www.amazon.com/CowboyStudio-NPT-04-Channel-Wireless-Receiver/dp/B002W3IXZW/ref=sr_1_2?ie=UTF8&qid=1326557006&sr=8-2You do not need anything else besides two AAA batteries to make this wireless flash trigger work.
But you will have to set the channel of the transmitter and receiver to match in order for the two units to work together. The little manual shows how to do this channel setting.
The transmitter, which goes in the hotshoe, does have a battery, too, but this battery comes with the transmitter. Supposedly, this battery lasts for something like 30,000 shots.
I own this wireless trigger, and use it exclusively in my home studio, with good results.
Note that you must set the flash power manually, on the Speedlite itself.
The easiest way to do the manual setup before use involves first putting the flash unit on the hotshoe of the camera. Then go to the External Speedlite control menu in the camera. Select Flash function settings. Select Flash mode. Select Manual.
While in this menu, select Wireless set. Select Disable. For some reason, disabling the wireless set must happen; otherwise, the wireless trigger will not function properly.
The flash unit saves and remembers these settings even after removal from the hotshoe.
You then set the flash power output directly on the flash unit. The flash unit manual explains this simple adjustment.
Note that the transmitter has a test button on top. Pressing this button fires the remote flash unit.