I recently came in to a bunch of ceiling mount omni-directional antennas that i don't have a need for. They are Cisco model AIR-ANT5959 antennas that use the rp-tnc connection. They are all new and in the box. I have one on a wrt54g right now that seems to be working great. I'm only asking for $10 a piece plus shipping.
here's the model info page:
please pm me if you're interested or for details.