Manipulate loops

Twinpitch by MusicSofts is a free live audio looper with built in effects.

Download here v1.2 (Win)
Download here v2.1 (Mac)

oXsampleWork by Flextone h.f.p. is an interface to modify playback of samples and record the results as a new audio file. It includes a sample loop player with variable envelope, playback speed, and dynamic filtering.

Download Win
Downlad Mac

Last but not least, Moduloop by Vex in Music is a standalone sound mangling/manipulation tool made using MAX/MSP, usefull for drum loop. You can import any wav or aiff loop as it syncs the BPM to the modulation matrix.. You can use sample CD loops, or loops processed in your favourite software (Wavosaur, Audacity, Peak, Wavelab, Soundforge etc). The loops can last as you wish. Once manipluated, you can then import your processed loops into other programs (e.g. recycle). Moduloop can record 'live' for on-the-fly processing of sound files. It can also be used as part of a live set-up using a laptop.

Download Win
Download Mac (not available)