I have used a Dell Axim 50v for 3 or 4 years..it has a ton of information on it. I recently acquired a HTC mobile phone using the Windows Mobile OS.

Is it possible two synchronize two mobile devices and have the desktop computer as the ultimate backup for all this personal information?..I would like to retain the Axim information for a while, til I am completely comfortable with the new phone (ideally, I would like to have both with the same up to date info).

I started the process of identifying the new phone to active sync, but it seems thus far to only accept a single identity as the mobile sync, so I stopped before losing the Axim link. Did I misinterpret the ActiveSync system?

Presumably this is done for security to avoid having any Mobile device be inserted into the cradle and immediately download all of the info?

You can setup two (or more) partnerships in Active Sync.
Start by making sure your HTC device name is unique: Start > Settings > System tab > About > Device ID tab.
Then connect your HTC device to your computer and follow the prompts to establish a new partnership. Check the boxes for the items you wish to sync from Outlook and they will transfer to the HTC device.

Confirmed, it works, I do sync, among others, my Motorola MPx220 with Active Sync on 2 notebooks, one running Outlook 2000 and the other Outlook 2003.