Along with today's iPod Shuffle line additions, Apple has released the promised 802.11n Enabler for compatible Macs.
The software is available via a software download from the Apple Store for $1.99 unless you buy the Airport Extreme base station which includes the software at no additional cost.
The $1.99 upgrade has been the focus of some controversy. The update had been originally priced at $4.99, but Apple slashed the price after an outpouring of discontent from users.