Yep, download this for your PC to convert files:
http://divx.ppccool.com/
(pocket divX Encoder)
and this as a player for your Axim:
http://tcpmp.corecodec.org/about
(tcpmp)
You won´t find better programs to convert movies for your PDA.
And the best, both are freeware !
Enjoy it, if you have any other questions, feel free to ask.
btw:
For your pda (vga) use bitrates from 900 to 1400 kbit/sec.
More bitrate = better quality but much bigger file sizes.
The Pocket DivX Encoder converts movies up to 2866 kit/sek.