If you have a BlackBerry and use the built-in Messages and Contacts apps, you can now search the email and contacts on your device using the new version of Google Mobile App.

Just type (or speak) your query - perhaps the name of the person who sent you the mail or a phrase from the text - and Google Mobile App will search through the emails and contacts on your device and return the results. You can quickly reply to an email or forward it on.

Source: google blog