Check this out.
http://www.poi2go.com/
PDA compatible
now, it support tomtom (native format), garmin, OCN (native favorites and converted POI), and mapopolis (need convert now but a native format will be added within few days).
If you like using POI in your navigation software, you will really love it.
Thinking about your are in a new city and want to find out all the "pizza" around...
Using your pda to connect to internet, download the dynamic poi into your pda navigation software.. ..then go ...