If you use Linux on your desktop, and you also happen to have a BlackBerry handheld device, you're probably aware that Research in Motion, the company that develops the BlackBerry platform, offers nothing in the way of support for its devices on Linux -- but the intrepid geeks in the free software world do. Thanks to to the efforts of the Barry and OpenSync projects, I just finished syncing my BlackBerry 8800 with my Evolution contacts on my Ubuntu 7.10 desktop.
If all you want to do is share data between your Linux box and the BlackBerry, no sweat. The 2GB Micro SD storage I inserted in my 8800 is available to my Linux system just like any other USB storage device. When I connect the USB cable to the BlackBerry, I simply say yes when Ubuntu asks if I want to enter Mass Storage Mode, and I can copy music and photos to the phone. I have run into a problem getting the audio for videos that were created with Kino to work correctly, but other than that, moving data back and forth between the PDA and the desktop "just works."