Thanks to all of you who participated in my Windows Phone 7 and Mango session today at Microsoft Raanana. It was a pleasure.
Following is the presentation for the first part, and demos for both parts.
Introduction to WP7 + Demos
The attached zip file contains WP7 Mango demos. You must download and install Windows Phone Developer Tools 7.1 Beta in order to build them.
Note: The audio files has been removed from AudioPlaybackAgentDemo\Audio. Please add your own audio file in order to run this demo.
As for the res of the demos, you can download the Windows Phone 7 Training Kit and Push Notification Recipe.
To learn more about Windows Phone Development, you can start with APP HUB. There are lot of demos and materials over there.
Also you may find a valuable information over the MSDN.