It's a free download [link], and requires Mac OS X 10.5.5 or better, BlackBerry device software version 4.2 or higher, and iTunes 7.2 or newer. Key features of the software include the ability to synchronize your iTunes library with your CrackBerry, sync calendars, contacts, and appointments, & add or delete apps and files.
This is the first time that Research In Motion (RIM) has developed their own solution for syncing Macs and BlackBerry handhelds. In the past, the company made a version of PocketMac for BlackBerry available at no cost to Mac-owning customers, and other third-party developers such as Mark/Space have had BlackBerry solutions available for many years.
Thanks to Storry for the tip!