When Apple introduced the new 802.11n-based AirPort Extreme Base Station during Macworld Expo 2007, it also announced that most Core 2 Duo Macs were already compatible once a software update was applied. Unless you are purchasing a new Base Station, however, the update will cost you $1.99.
Apple 802.11n Upgrade to Cost $1.99
Apple 802.11n Upgrade to Cost $1.99