Yes. Use the Airport utility (In the Utilities folder within the Applications folder) to Manually set up the Express to join the existing network.
There is no such Apple product by the name of 'Apple Express'. Unless you are referring to the Airport Express, then yes, it does work with Apple TV.
A wireless network can be extended with a Airport express unit. Apple has a support page explaining the set up (See links below). An Xbox 360 can simply connect to this wireless network or you can probably arrange the set up to use an Ethernet connection.
Apple's Airport Express comes with software that can be used with a PC. The requirements are a PC with Windows XP (SP2) or Windows Vista, CD drive, Ethernet or wireless networking capability. To connect to the network a PC needs 802.11a/b/g/n capability.
The airport code for Apple Valley Airport - California - is APV.
an apple
An Apple airport card is used to connect an Apple product to the internet at an airport location. You can find many of these for sale on Ebay, ranging in price.
The simplest system is an Apple Airport Express, a wireless hotspot with an audio output. You use iTunes to play the music, and the Express connects to an input on your receiver.
The simplest system is an Apple Airport Express, a wireless hotspot with an audio output. You use iTunes to play the music, and the Express connects to an input on your receiver.Read more: What_products_are_available_to_play_music_wirelessly_from_your_laptop_to_your_home_theater_system
The newest revision of Apple's AirPort extreme, with the latest firmware updates applied, will work with Apple's Time Machine.
The first generation of the Apple AirPort Extreme began shipping on January 9th, 2007. They shipped until march 19th, 2008 when the second generation Apple AirPort Extreme was introduced.
Airport
In the recent past, Apple Inc. has referred to 802.11(x) networking as AirPort. 802.11a/b was referred to as simply AirPort 802.11g was referred to as AirPort Extreme 802.11n has been referred to as AirPort and AirPort Extreme. As of OS X 10.7 Lion, Apple began referring to 802.11(x) as Wi-Fi.