Unless you have very challenging triggering conditions necessitating fairly long rangeremote syching and with line of sight blocked, I would simply use the built in sync triggering of the lighting units, which most contemporary lighting units like Alien Bees support. Usually these self-powered lighting units can be triggered in sync by a shoe-mounted infra-red trigger, which is really a low-power infra-red filtered flash outputting a light-pulse to trigger flash units with built-in slave sensors.

To add to what David said. The gold standard in radio controls is the Pocket Wizard. Each unit can be either a transmitter or receiver and they cost about $200 each. The advantage is that they are radio and not optical which is line of sight. Also, if you use Nikon, look into their iTTL wireless control (line of sight also) of the SB-800 and SB-600 flashes from their camera bodies.

It also depends on what you shoot and how/where you shoot it. I use these fantastic slaves called "Flashwaves". They're available in Canada, at least, though I haven't heard much about them in the States. They don't have the range of the PWs, but then they only cost about 1/4 the price. I use mine exclusively in a studio environment and have never had any problems. They don't require line of sight, have attachments for non-PC corded strobes (like my Pentax ones), and weigh next to nothing. Check 'em out.