Radmin cannot work on a PDA. We are planning to port Remote Administrator to PDA's (Pocket PC/Windows Mobile) in the future, but now we are extremely busy with beta-testing of Radmin 3.0. The development of PDA version was not started yet.
Just found this site today...and am impressed with the software features (soon to try). Been using the free version (limited to remote access without file transfer etc) of "logmein" I am mentioning it here only because it does have pocket pc capability. I use it that way successfully. Their paid version is too expensive (a monthly fee, etc.)...but the freebie might be a good option for ppc use until Radmin gets their ppc feature up and running. Came here to expand my horizons.