Apple take their wireless routers to the next level by introducing a new way of using both a 2.4GHz frequency, for wireless ‘G’ devices such as the iPhone, while at the same time sending out a 5GHz frequency for wireless ‘N’ devices. This results in must faster transfers and range, while still retaining compatibility with the older wireless G spec. Currently you must choose to run your Time Capsule or AEBS in either 2.4GHz or 5GHz mode and not a mix of the two. It would have been nice if this was possible with a firmware update but alas I suspect it is a hardware update involving another transmittor. Apple tell us..

Simultaneous dual-band 802.11n Wi-Fi base station.
Time Capsule is also a full-featured 802.11n Wi-Fi base station. And now it operates in 2.4GHz and 5GHz bands simultaneously to ensure the best possible performance and range for all your Wi-Fi devices

Prices are as follows:

AirPort Extreme Base Station
£139.00

Time Capsule 500GB
£229.00

Time Capsule 1TB
£379.00