There really isn't a speed drift, per se. Like Ting said, the initiation of the drift is the named part, because it determines the remainder of the drift really. No matter how you enter a drift, maintaining it and exiting from it are always the same, just timing and once you got it down for one style you got it down for all.
As far as styles, these are the ones I can remember off the top of my head, if anyone else remembers any others please chime in:
Powerslide / Power Over: Use the accelerator to break the rear tires lose and send the car sideways
Side: e-brake (nuff said)
Brake drift: Use the brakes to bring the rear-end out
Shift lock: Shift down entering a corner and engage the clutch quickly with some throttle to break the tires lose. (In GT3 this is just powersliding because there is no clutch).
Feint: Swing the rear-end toward the inside of the corner before-hand, then immediately transfer weight back to the outside to get the rear-end out.
Accel off: Lift the throttle suddenly while entering a corner hard to transfer the weight off the back of the car so that the rear-end will swing out on its own.