Lots of stuff. Work your legs mostly, and pay special attention to your hamstrings (SLDL, Good Mornings, Curls), and for explosiveness you should try the olympic lifts and all their variations. There is a program called "Air Alert" or something like that, check it out.
speed is about power. try doing 80 metre sprints, do one then a short rest and then repeat. Along with the weights (and remember hamstrings) you need to practice sprinting if speed is what you are after. Plyometric jumps for vertical, Air Alert is supposed to be good but intense.