I have seen a couple of questions in this thread asking WHY the stereo
headphone adapters don't seem to work for the Blackberry.
The reason MOST don't work is because they don't even have the
(REQUIRED) 4-conductor plug.
Others don't work because they do not include the proper resistor
(or equivalent impedance) to "simulate" the presence of the external
microphone that the STEREO headphones sold for the 8100 have.
You can build your own stereo adapter for the pearl, the plans for the
one I built are posted at the link below, as is a picture of my home-built
adapter. BE CAREFUL purchasing on the internet as even some of the
"stereo headphones for Blackberry Pearl 8100" sold on ebay (such as
those sold under that title on eBay by Accessory Export) do not even
have the correct plug and actually route the LEFT channel audio output
to BOTH headphones!
Here is the link to the plans to build you own. You will need to view
this page and the .PDF file it points to on an internet connected
computer as the pages are NOT formatted to display correctly on
the Blackberry: Use ANY Stereo Headphones with the Blackberry Pearl
You can build your own adapter for about $6 _IF_ you can solder!
The one I built works with every stereo headphones I have tried, so far
about 6 pairs, also provides proper output to external stereos, etc!
Have fun and enjoy the high quality stereo output of the Pearl!