synthtopia has put together a little overview of freeware apps for PC and Mac all of which can be used to glitch up your audio.
is a free Windows 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.
is a free AU plugin from Smartelectronix. When synchronised to tempo, this plugin will take the incoming audio and re-arrange it in a musically sensible way. Think of it as a realtime ReCyCle with fun options.
is a collection of free VST & Audio Unit plugins designed to destroy your music in creative ways. Plugins include Buffer Overide (below), Scrubby & Geometer.
is a monster of a plugin, giving you control over all sorts of parameters for glitching up your audio:
is a peculiar collection of instruments that you can patch togheter with a modular matrix. The suite features four stereo loopable wave readers/writers with different random loop point algorithms, one wavetable oscillator, a sonic reducer, 3/4/5 bands parametric EQ, an amazing sonic disgregator, a granular re-synthesis engine, a ring modulator, a 5 stereo tracks mixer, and more.