Windows Phone Thoughts: Introducing the Windows Mobile API Usage Tool

"The API Usage Tool scans your Windows Mobile applications (in cab, msi, or binary formats), performs static analysis, and reports on the usage of APIs and other system resources. Our application compatibility team has been using the tool for several months now to ensure that we have good coverage of our public SDK when we do testing with 3rd party applications, as well as to help guide resource allocation and investments toward the most frequently used APIs."

This program will scan your mobile app and report on the used APIs, including depreciated APIs and export it to a file. MS would like to collect these statistics to aid in their compatibility planning. More details, including the address to submit the info on your file are at the site linked to above.