F-Secure has seen a proof of concept piece of adware which is targeted specifically at OS X.
http://www.theregister.com/2006/11/24/mac_os_x_adware/
http://www.f-secure.com/weblog/archi....html#00001030
Its not amazingly clever, and isnt very complex but does prove that adware can be made for OS X, as well as for Windows.
