Go here http://developer.sprint.com/site/global/home/p_home.jsp to register. After you register at the site go here https://developer.sprint.com/searchHandsets.do and follow the steps exactly. Its an easy process and will not harm your phone.
I triedusing the developer's kit to sign apps as per the instructions. Enabled my phone and everything by the book. Isigned a version of Google maps as a tryout. It froze on the terms and conditions screens. Anyone know what i'm doing wrong?