The Google Places Autocomplete API for WP7 is a project for WP7 developers to use when implementing an autocomplete box in their application. This project provides an easy non-blocking way to get fast results from the Google Places Autocomplete API.
*Please note that the use of this project requires that you create a Google API account and comply with their developer guidelines, e.g. placement of the Google logo etc.
Here is a video showing the use of the API with an AutoComplete box from the Silverlight Toolkit. The emulator was connected over a 3G connection with poor signal, and the input delay was set to 200ms. Your results may vary based on the input delay and your data connection.