Hi.
It is always recommended to back up your PDA first, use the facility in Activesync to do this as an upgrade will always wipe all programs and data you have stored.
Unfortunately, their is no PDA equivalent of the Automatic updates on PC's , the only way you will find updates is to look at Dell's site or watch this board for news.
Look at Dell.com with the following link
http://support.euro.dell.com/support...os=PPM&osl=EN#
Make sute you select the correct one for your X51 ( ie x51 or x51V).
You then download to you PC and follow the instructions.
Yes the upgrade is via Activesync and the USB cradle with external power.
The Dell instructions are very easy to follow and you should have no problems. Again when it gives you the opportunity to back up the ROM, I do suggest you do this also.