When RealPlayer SP came out 6 months ago many Mac users complained that it was PC only. The app was a real move forward for Real and really shook off my old misgivings about the Real brand. The application allows you to easily take videos from the internet and download them to your Mac and automatically convert them for viewing on your BlackBerry. I have not had a chance to try it on my Mac yet since Handbrake works fine but let me know if you give it a shot.
In short RealPlayer SP makes it easy to download flash videos in your Mac browser and scale them to fit correctly and play on your mobile devices. From what Simon @IntoMobile mentions the Mac version handles video conversions slightly different from the PC version but it should still work.
You can find RealPlayer for Mac at www.real.com/mac/realplayer