The company behind the Xbox 360 is Microsoft Corporation. Now, Microsoft have a huge technological empire of a business that spreads out across the globe. As such, there is not just one address where you can contact them; there are hundreds.
However, residents in the US may like their head office's address. Being an American company, this is also Microsoft's world headquarters. Anyone who wishes to write to Microsoft in the US, possibly for support purposes, should use the following address:
One Microsoft Way,
Tel: (425) 882-8080
Fax: (425) 706-7329
However, for users in the UK, a different address is needed (obviously). And that address is:
Thames Valley Park,
Tel: 0844 800 2400
Rest Of The World
Obviously, these aren't the only two places the Microsoft 'empire' extends to. And there are numerous offices across the world in hundreds of cities. Luckily, Microsoft has set-up a handy website where you can find your nearest Microsoft office, and continue on to the contact details therein.
That website, is... HERE! (click the link)