MS already did something like that before:
http://en.wikipedia.org/wiki/Smart_Personal_Objects_Technology
For 25 bucks more, get the 620. It works with AT&T's 3G network. The 520 seems to be 900/2100 only which is weeeeird.
Edit: Yup
http://www.nokia.com/global/products/phone/lumia520/specifications/
Thanks for the reply. I'll most likely get the Lumia 620.