I just received one of these. By popular acclaim of my drunken compatriots at Fancypants Village, it is the Best Headset Evar. And the connector works by default with my Treo and several other phones tried.

It would be better if it had an "answer call" button, or was bluetooth, or came with a rotary dial body. But still. Pretty awesome. Sound quality is excellent. $35.

(See also.)