The software is located at: http://chirp.danplanet.com on the Internet.
As of Feb. 27, 2014 these are the radios supported by the software.
They are adding radios on a regular basis.
Other Data Sources
I suggest loading the Daily Build version of the software to give you all the recent radios that Chip can work with. The Daily Builds are located at http://trac.chirp.danplanet.com/chirp_daily/LATEST/ and it is always best to load the ZIP version.
There are versions of Chirp that support the Macintosh as well.
I found this wonderful demonstration on how to run the software and program multiple radios using Chirp: