If you are a student developer and want a free Mango Phone there are only 5 easy steps to follow:

1. Make sure you’re registered for DreamSpark
2. Download and install Expression Studio Ultimate and the new Mango Windows Phone Developer Tools (available free as a member of DreamSpark)
3. Get the free Sketchflow Template for Windows Phone and create a Sketchflow mock-up of your app
4. Post the Sketchflow mock-up somewhere online and tweet out the link using the hash tag #WPAppItUp
5. We will review all prototypes and will contact the developers who submit the best ones and send them a special Mango developer device

There are 50 available phones and already 20 have been taken, but that leaves another 30 for you to come across!!!

You can find some examples on the official blog here:

http://windowsteamblog.com/windows_phone/b/wpdev/archive/2011/07/29/mango-device-love-for-wpappitup-prototypes.aspx

So get your hands dirty as fast as you can! It's worth it! :)