dj set... do you use a mixer/powered mixer or such then through to the speakers/outputs etc? if so then you'd probably just need a stereo 3.5mm (or 1/8in - from the pc) stereo jack to 2x rca (or whatever you're planning to plug it to) example like the y connector aforementioned above, then plug that into a line in or an available channel..
if the speakers are self powered then you could possibly connect them directly.. i think the standards are either XLR, TS (6.5mm jack), or speakon connections... can you tell us what model/make or connections it takes? as well as how many of these you're planning to run (1 speaker, 2 speakers (L-R), 2 speakers + sub etc) and if it is running through anything/self powered..