It's a long thread, but I'd suggest you read
this thread first. It has a good discussion on the power demands of the Axim series and how the pins on the bottom connector are configured to protect against those demands on the USB ports. There are some good cables out there, and some not-so-good. Just be aware that any that say they can charge and sync at the same time are bypassing that overload protection and may damage the USB port if you connect up with a really low battery.