130 Free to use and modify Metro Icons...
A couple of my favorite things... Paint.Net and Windows Phone 7 (and using the one to create App and Tile icons for the other)
Sometimes a picture says… Photoshop Design Templates (and other design resources) for Windows Phone 7
Application Bar Icons for your Windows Phone 7 development
A Windows Phone 7 Development/Design Guidelines/Certification Requirements Cheat sheet/Checklist
The Noun Project, XAML’ified… or The Noun Project converted for you to XAML and PNG’s
“The Noun Project” + SVG + Free + Metro like look and feel + 500 = Happy Windows Phone 7 Developers