Subsun has released Wobbles, a free effect plug-in for Mac.
Wobbles is a free-ware vibrato plugin for Mac OSX 10.4 and higher.
The effect features adjustable shape, depth and speed. Chorus and phaser type effects can also be achieved by using the dry/wet knob.
It has not been widely tested, so please let me know if you have problems! If there is interest in this plugin then I might update it with a couple more features (tempo syncing, custom LFO shapes).
Wobbles is available as a freewave effect plug-in for Mac OSX 10.4 and higher (VST/AU).
More information: Subsun (website no longer available)