HN user
Guys - your should really try CallmyName app. It gives a much more comprehensive solution - it includes phone number, email, address, skype ID, Twitter, FB, picture, etc And most of all it is absolutely FREE...
There is exactly such a "DNS" that is working WW (not just on one network...) - look at the CallmyName application - registration there is absolutely free!
Why the heck should I pay $36/yr for a service that can work only on Sprint's network when you can register your call name for FREE with a great application like CallmyName. Me and most of my friends have call-names with CallmyName and it works superbly well. I highly recommended to try it and get you call name ASAP....