Some Important links on WP7

app hub registration walkthrough

http://create.msdn.com/en-US/home/about/developer_registration_walkthrough

App hub application submission walkthrough

http://create.msdn.com/en-US/home/about/app_submission_walkthrough

Windows Phone developer dashboard walkthrough

http://create.msdn.com/en-US/home/about/developer_dashboard_walkthrough

Application Certification Requirements for Windows Phone

http://msdn.microsoft.com/en-us/library/hh184843(v=VS.92).aspx