The Windows Phone 7 Developer Contest is now open, with a deadline of August 15th. To participate, developers must create an app that uses the Twilio API, utilizing the free Windows Phone 7 Developer Tools and the updated TwilioApi library, which simplifies the process of sending SMS messages. The best submission will win a netbook and $100 in Twilio credit. Developers are encouraged to submit their apps or provide a screencast demonstrating its functionality, with resources available on the Twilio website for assistance and inspiration.