Airport Extreme to Support 802.11n with 5GHz Band

Unlike most of the current pre-drafted 802.11n-based devices, the new Airport Express base station supports, in addition to the standard 2.4GHz band used for 802.11b/g, the 5GHz band. This is a good point as the 2.4GHz is rather overloaded in cities, most wireless devices are using it (WiFi, but also DECT phones, etc.).
When comparing performance of both frequencies, one can read on the web and find one way or the other; so we would recommend reading an old article from wi-fiplanet.com about 802.11a and g.
As reported by MacWorld, it might be a problem in some countries where regulations concerning the 5GHz band are more strict.
To reach the highest transfer speed with 802.11n and its 5GHz band, one needs to use simultaneously several channels, so one has to enlarge the bandwidth to 40MHz. So Apple might offer in EU countries a specific Airport Extreme base station, with different level of options concerning channel selections.