Do you remember the nifty new wireless access point which Apple released recently, the one which streams music wirelessly from your iTunes library? Arstechnica has a review of the device.
Great little device, I ordered one right away but was put off by the fact that it only extends AirPort Extreme APs so I cancelled my order a couple of days ago. Reading the review I learn that it will work with any existing wireless network but as a client it won't extend it.
Or so Apple would have you think Ars has found that the Express WILL extend certain third party access points such as the WRT54G from Linksys. This is great news as the Linksys AP has a lot more features and retails for one fourth of what you will have to shell out for the AirPort Extreme. That is a sweet deal and I may have to look into it soon as I think the Express is one hell of a little device.