I have two phones, my ppc-6700 and my samsung a900m. Until recently, I only used my ppc-6700 because I could check my email and gps but now my a900 is my primary phone.

I can run the following apps that are kick but on my a900:
-java gmail
-java Telenav GPS

The second is really the kicker. Ringerpost has some hacked versions where you don't need to pay anything per month and it works without a bluetooth gps or anything. I can be lost on the street and look up directions. Moreover, it has even better features like finding lowest gas prices or other POIs via the internet (like google maps on the phone).

Has anyone got the free java version to work on the ppc-6700?

For the a900, I'd suggest an a900 forum.

For the java apps, I use the MIDlet manager to run the gmail app. I also had google earth installed and working at one point as well. No experience with Telenav.

What directories do you put the .jar and .jad files?

My temp download directory. I downloaded the .jad file, double-tapped in Resco to open with MIDlet and it ask if you wanted to install the file. I have had mixed success with installing other java games and applications so I only really only use it for the gmail app. Do a little searching for MIDlet as I found a pretty good tutorial about this program a while back (obviously can't remember now though).