I know that there are many Mac users who are frustrated by the BlackBerry support on a Mac. RIM has offered PocketMac as a solution but many users have flocked to the Missing Sync application from Mark/space. Unlike PocketMac, this application costs $39.95 for the pleasure of using your Mac with your BlackBerry. It seems like they are still having problems with OS X Leopard compatibility so they are recommending you hold off for now.
Recently they released the minor v1.0.2 update to The Missing Sync for BlackBerry, which adds support for unspecified new phones, while also alleviating connection problems reported by some users. They have also added some fixes for Mac OS X Leopard, including Time Machine backup issues.
Forthcoming for all versions of the program is a major update, which has no date attached but will the first update deliberately targeted at Leopard compatibility. Mark/Space in fact recommends that users avoid using Missing Sync with Leopard until the update is available, since there are known issues such as crashes.