Pretty good price from Amazon, includes free delivery. Info from Amazon:
Offering the best wireless connection available on any console.
Perfect network for media streaming (downloading HD movies)
Best solution for running media-intensive files such as video, music & photos
Offers never seen increased speed, coverage and reliability
Works with existing 802.11g and 802.11b wireless routers and access points (backwards-compatible)
Based on 802.11n draft, Wireless N enables multiple receivers and transmitters to send and receive data