There is quite a bit written on how to handle tombstoning on a Windows Phone. Most of the guidance is for code-behind developers. Here is an MSDN article ( How to: Preserve and Restore Page State for Windows Phone ) that shows how to use the Page’s OnNavigatedTo...

We are just about to release an update to the Windows Phone 7 Developer Guide that p&p shipped one year ago. The updated guidance takes the same scenario but updates the phone client application leveraging features in the Windows Phone 7.1 OS Mango...