After the item mysteriously appeared in a UK supermarket this weekend, Microsoft has finally offered a North American release date for the Xbox 360 Wireless N Networking Adapter -- and it's right now. Or, rather, "this week," as the announcement puts it. The new version of the official Wi-Fi adapter will retail for the same $99.99 that the first version commanded (though Amazon has it for $87.99 right now, and the old one at $76.49).

The Wireless Adapter N adds support for the 802.11n protocol, which should allow for higher-speed wireless connections. It also adds a second antenna, which allows for symmetry. Given its high price, it may cause buyers to suffer like the 802.11g did.

Update: We've confirmed with Microsoft that the original 802.11b/g adapter will only be available while supplies last.

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