The 3.5 connector is a pretty standard item for cell phones. I'd go to Uber
Mart and buy one of their cellphone headsets with a similar plug. You
should be able to get one for $10 or less. My Nokia cellphone uses exactly
one of these 3.5 plugs to connect a cellphone headset. Once you have a
sacrificial cellphone headset, plug it into the Axim to confirm it works as
you hope. Then you can dissect the cellphone headset cable to sort out
which wires are for mic and which for earphone. Once you have the wires
labled it's a matter of attaching the proper plugs to the ends of the wire.
I've found the guys on the rec.electronics.basic news group to be polite and
helpful if you need to attenuate the signal.

Maybe Dell can tell you more about the mic/earphone plug, such as what
cellphone uses a similar plug. If you know what cellphone uses the same 3.5
plug you can buy an intercom/cellphone adapter which I've seen advertised in
AOPA Pilot. I think these cost approximately $100. These have the benefit
of being properly matched for cellphone and intercom, which my hack job
described above does not.

I have a Dell X3i that I use for notes and MP3 playback all night. I'd
suggest it might be better to use a dedicated digital recorder. These are
available at Uber Mart for well under $100 and provide 3 or 4 hours of
digital recording. Several times I've had the Dell lockup when
multi-tasking which causes me to lose the notes that were open at the time,
never info that was already saved.

--

Scott