Building a Game for WP7 (WindowsPhone 7)

Hello,
I’m new to WP7 application development, the question is, I want to make a game for WP7 so i want to ask that from where should i get start and what are the necessary softwares or application I will need to build a game for WP7.
Please Rep ASAP.

Thanks in Advance! :):sure:

P.S: The thing I want to know is actually the usage of the necessary application to develop a WP7 game, I mean to say that, (you)must tel me the usage of every application you are going to refer me for the development.