Its original purpose was to provide a simple means of getting basic sound effects into a game for those people who were working hard to get their entries done within the 48 hours and didn't have time to spend looking for suitable ways of doing this.
There already was a Mac port, but I felt a sudden urge to make one with a native Mac UI, add some proper save/load, and learn Core Data and Bindings while at it. My version's called cfxr (as in "Cocoa sfxr").
Note that I'm not the author of sfxr, I've just ported it. (See also: my announcement blog post)
Torley on youtube made a screencast of cfxr! Check it out:
DrPetter's original sfxrSearch for "mac" on sfxr's announce entry to download sfxr for mac. Make sure you get the right one depending on if you're on ppc or intel. (cfxr is universal and works fine on both).
v0.2.1 (2011 08 28): Fixed choppy sound under Mac OS X 10.7 Lion. Dropped PPC support since development tools don't support it anymore.
v0.2.0 (2010 06 01): Added copy-paste of sounds, and the sound is played when you change a setting
v0.1.5 (2009 09 03): Added looping, and the sliders are now continuous (don't have to release the mouse button to hear the changes).
v0.1.3 (2008 05 19): Forgot to bundle SDL.
v0.1.1 (2008 05 18): Initial release.