Question : Where can I find Microsoft's DDK ?

Please give me URL where I can find DDK ?

Answer : Where can I find Microsoft's DDK ?

You can find lots of info at

http://www.microsoft.com/msdn/   and
http://www.microsoft.com/hwdev/  and the DDK documentation at
http://premium.microsoft.com/msdn/library/  (you need to register for this one)

but if you need the DDK you have to subscribe to MSDN (Microsoft Developer Network). Only the Professional ($499US) and Universal subscription ($1999*-$2499US) includes the DDK.
You can read more at http://www.microsoft.com/msdn/join/subscriptions.htm

Regards
Jesper