Ok, thanks for the responses/support
I think i've tracked down the problem, and the "typical" solution did fix it - basically i've got to turn down the volume to the lowest possible setting - at wich point i've elliminated the echo for the listener, but have trouble hearing what the listener is saying - not sure if its a good trade off, but its a start.
So any idea why this is the case - I've had a dozen or so good cell's in the past an none of done this since the early 90's. - so is this caused by crapy lowquality components in the ipaq, or poor design or what?