Hi Stephan,
thanks a lot. I now went through the list at http://wiki.openstreetmap.org/wiki/Routing#Onboard.2FOffline but unfortunately I didn’t find a software fitting my needs.
I could start Gosmore. However,
- I couldn’t load NW-Germany, it said: “map too big”. So I tried with Belgium…
- I don’t know, if it didn’t detect my display’s resolution correctly. However, I just have 3 buttons, it asks me some strange questions, but I didn’t make it to calculate a route for me.
- It crashed multiple times in the few minutes I was testing it.
The other applications seem to be either Linux only or commercial or Java. However, my PDA didn’t want to open a .jar-file. On the homepage of Sun they tell either the OEM should have shipped Java, or I couldn’t have Java. And I didn’t find an alternative JRE for WinCE 
So, does someone know a JRE for WinCE 4.2? Or are there other applications for WinCE?
And is there experience with Linux / Openmoko? Would I get a good navigation system with the Neo Freerunner?
Thanks
Mirko