The Beatmaker revolution

It's not free but very cheap (approx USD 20) for having an equivalent of Akai MPC2000 within your iphone and/or your ipodtouch! I tried it during my last trip in Ibiza (especially waiting for my flight in the airport) and it was not only entertainement but indeed you can consider make a real track with it. The only negative aspect is that the general volume button is not implemented yet which is really annoying so plug headphones for a better experience!

Features list
16 Sample Trigger pads with individual controls for:Volume, Mute and Reverse playbackAutomatic and manual sample duration settings and tonality controlChannel routing (Main, FX channels)Edit samples start/end positions with the wave editorIndividual sample loading on each pad, auto-chop samplesEdit multiple controls at once with handful selection toolInstant sample muting and reversing modes
Step sequencer with velocity and groove editors:Live sequencing of sample triggerUnlimited patterns creationVelocity and groove editors
Song sequencer:Sequencing of patterns on the song timeline, liveTime-line, loop, tempo and playback control via foldable transport barSuited for live performances !
Live pattern recording:Tap the trigger and record to a new patternCreate an unlimited number of recoding patternsQuantization
Two effects channels, each one containing 3 FX racks:Synchronized Delay3-Band EqualizerBit-Crusher
Share your audio material from and to your computer with BeatPack:
Additional functionalities:Load & Save controls (Kits & Projects)Song export to audio fileInline documentationIntua RSS viewerKit description pannelBeatPack servers configuration
Shipped with an initial soundbank and artist kits

Link here

LLoop for live stage

lloopp is a software written in max/msp, designed for live-improvising. lloopp is freeware, open source. lloopp is written by artists who use this very software for their performances. lloopp needs max/msp installed. the visual part of lloopp also needs jitter.

downloads
uploads
screenshots

Glitch your loops for free

Glitch is a VST plug-in effect for Windows-based systems running a VST 2.3 compatible host.Glitch chops up your audio in real-time and applies a variety of effects which can either be chosen at random, manually sequenced, or a mixture of both. The sounds it generates range from quite subtle to extremely bizarre, depending on how much you tweak the controls.

Download here

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)