jremington:
Here is another one: a "long range" Bluetooth module from DX.com, with a fake antenna. Adjust for best reception!
(photo on scanlime.org)
What's the world coming to?
Oh - hang on, I think I know. 
I was about to mention the problems in connecting an external antenna to one of these "on-board" ones.
Firstly, you cannot just connect the two together as you will be altering the impedance and the pattern of the external and internal ones are likely to interfere.
Secondly, given that you do disconnect the on-board one, you probably have no idea of the impedance at the point you connect into. It is more than likely not 50 Ohms.