go to http://circuitcity.com and then look for the TRENDnet 54Mbps Wireless G USB Adapter and it should work for your 360 and it only cost 24.99 better than 100 dollars for the Microsoft one
No only if you have a wireless adaptor!
No. You need a wireless router, though you don't necessarily need a computer.
The adapters are all the same, all configured to work with similar routers. The routers used between the US and EU are not much different so the adapter should work fine.
Yes. All you need to do is re-sync it to their Xbox360.
yes
One can purchase the cheapest Xbox360 at Tech Bargains, Amazon, eBay, Penny Arcade, Big W, Tech Land, Best Buy, Cash Generator, Console Prices, Price Me and many others.
the cheapest places: Ebay.com Amazon.com Geeks.com (Recommended)
They are all the same price. Do not get any third party wireless adapters because they are not as good.
An Xbox 360 wireless network adapter costs around $59.16 from websites such as Amazon. The adaptor allows players to connect their Xbox to their routers wirelessly.
No
You can use your Xbox360 Wireless headset to play!
No you must have an Xbox360 controller. There are both wireless and wired ones. I would reccommend getting a "Play and Charge Kit" if you get wireless.