You mean use the drums to trigger samples or loops. To that you need elec drum pads, drum module, and a sampler.
What you do is connect the module to the sampler via midi. Then you have to match up the midi note #(s).
To eliminate the drum module part of this you could get an akai s900 sampler w/ an 8 trigger input expansion board.
any akai sampler will hep you out here. Also, try the Akai MP2000XL. that's a great one with drum samples to die for. There's a great Alesis unit available aswell. although i don't like the tom sounds.