One of my favorite Twitter clients is coming to the Mac, and the public alpha (which is guaranteed to have bugs) can be “tested” by everyone who has Mac OS X 10.7 or 10.8 for free:
Developing for the Mac is no easy task, especially a full-featured Twitter client. However, we’ve gotten to a point where while not complete, it is useable. We’ve decided to release it as a public alpha to a) motivate us to finish faster, and b) get feedback to help us build the best Mac incarnation of Tweetbot we can make. You can love it or hate it, but rest assured it will only get much much better from here.