i use mine with Cactus V2s's. you techically only need 1 transmitter and 1 receiver, even if you have 2 lights. the genesis's have photocells, so as long as one goes off, the other will as well. i did, however, pick up a second receiver to hook up to my 580EX.
the genesis lights come with a pc to 1/8" sync cord. you can plug the pc end into the cactus receiver, and the 1/8" end into the strobe itself. they really work great, and i've done about 15 shoots now with them and have only had 1 or 2 misfires. the cactuses don't play well with wireless triggers, as an FYI.
i love these lights. they're not 100% consistent every time, but for the most part, i think for what you pay, they're the best bang-for-your-buck lights around.
you can also pick up amvona softboxes real cheap to use with these guys. a little macguyver-ing is required, but boy do they work. i have an amvona octabank and a brolly-style umbrella from them. both for under $100.