DivX has released DivX 7 for Mac which is a free download that provides everything you need to enjoy high-quality digital videos on your computer, including high definition H.264 (.mkv) videos with AAC audio and videos created using all previous versions of DivX technology.
You can also play your DivX files (.divx, .avi) on millions of DivX Certified devices today. Look for DivX Plus HD Certified devices soon that will support playback of all DivX and DivX Plus HD files, as well as .mkv (H.264/AAC) videos from the Internet.
The free DivX for Mac download includes trial versions of the DivX Pro Codec (6-month trial) and DivX Converter (15-day trial). Purchase DivX Pro 7 for Mac for US$19.99 to get full versions of DivX Pro Codec and DivX Converter.
DivX for is optimized for Mac OS X 10.4 and above.
More info and download links here.