Program written by The Propellorheads (also responsible for the seminal Rebirth) called Re-Cycle (originally for the Atari ST, now for the PC and Mac) which virtually invented the breakbeat, especially in the manic form found in drum & bass music.

When fed a sample, it automatically detects the beats within it and cuts it into as many separate smaller samples as you require, which you can then transmit (via midi or scsi) back to your hardware sampler or load into your appropriate software.
The real magic of the program is that is also generates you a midi file which, when loaded into your sequencer and played into the sampler will recreate your original loop, or, more usefully, allows you to have enormous fun cutting up and changing the original loop into something far more crazed and frenzied.