RealPlayer SP Beta for Mac takes care of the download and conversion, making this program in my opinion the easiest way to get videos from the web onto your BlackBerry® without sacrificing video or audio quality. I have used the PC version which has been out of beta for quite some time and have never been disappointed. I hope the same holds true for the MAC version. Please feel free to leave a comment and let everyone know how it goes if you are using a MAC.
You can pick up RealPlayer SP Beta for Mac by going HERE!
How to video for the PC version is HERE!