TeoreX has released PhotoScissors, a Mac compatible tool for simple picture editing. It lets you remove unnecessary background from photos via mouse gestures.
You identify areas to keep and areas to cut out with very rough strokes and the program automatically does the rest. The program automatically applies anti-aliasing filters for smooth edges of the cutout, and quickly processes even larger images.
The price for a single license of PhotoScissors is US$19.99. PhotoScissors is available both for Mac OS X and Windows users. Go to http://www.photoscissors.com/ for more info.