Peter,
I am also looking into using my Dell Axim as a universal remote. While I have no way to personally test this, as my Axim is still in the unopened box in my apartment, the following will work:
Head over to
PDAWin
and download (and eventually buy) TV Remote Controller 5.4
This version has support for the AXIM.
The next major problem, is to increase the IR range of the Axim. I just got an email confirmation from the maker of this part. While his site has not been updated yet, his card has been tested with the Axim.
PDA-IR
Good luck, and make sure to post your results!
Cory