At the Black Hat security conference one Jon Ellch and David Maynor have created quite a stir around the computing world. They used low level hacks to take advantage of a MacBook via the Wi-Fi card drivers. There is a lot of confusion bubbling around this situation because Ellch and Maynor performed the hack on a MacBook, but the hack itself isn't limited to the Apple laptop. Hell, they weren't even using the wireless adapter shipped with the MacBook. There are a handful of Wi-Fi adapters with this security flaw.
They did it on the MacBook because the "smugness on security" that most Mac users have and the fact that Maynor wants to "stab one of those users in the eye with a cigarette" regarding the actors in the latest Apple commercials. Regardless, everyone may want to consider turning off your Wi-Fi when it isn't in use until more info is divulged about this security flaw.
Hijacking a Macbook in 60 Seconds or Less [Washington Post]