Audioquest has some good info on that here http://www.audioquest.com/ ; select Cable Theory. Biwiring is using 2 cables or 2 parts of one cable per speaker to sort of divide and conquer, rather the way speaker designers use different drivers in a speaker for different frequency bands. It's LOTS more complicated than that, of course, but I believe it's a valid way to improve the sound of a system. However, the improvement, Other Things Being Equal and of course other things are NEVER equal, is IMO down to a tenth or 2 of a point on the 10 scale. IOW, many other improvements will be FAR more audible than the improvements from biwiring, OTBE.
If your speakers have TWO pairs of input jacks for each system, labeled something like Low and High, they're biwirable.
.