A release candidate, and pretty much in the nick of time if some rumors about the impending release of a certain operating system are to be believed.
Speaking of which, there are a number of smallish fixes in place to provide better compatibility with the upcoming Mac OS X 10.6 “Snow Leopard”, along with some other fun bug fixes and localization fixes for our international users.
Read all about it at the beta download page, and peruse the historical release notes if you so choose.