This is a product by Kimbrough - http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXNN07&P=7

In Australia you can get them from Model Flight -
http://www.modelflight.com.au

The issue I had with this product is that it is made with nylon which in testing I found that slippage was a issue. This was due to the fact that I was forced to use a fairly small diameter wire for the coupling due to the thickness of the aileron.

I ended up turing up some aluminium collars that used the nylon collar as the link to the servo, and replaced the nylon insert with an aluminium insert.

This diagram is an exploded view of the modified collar I machined. (click on image for larger view)

Below are some images of the system I used. If you look closely, you can see the nylon inserts at the servo end.

(click on an image for a larger view)

(click on an image for a larger view)

Alternative method for using aluminium drive couplings:

http://www.irfmachineworks.com/rds/