AT&T Tether

http://www.xda-developers.com/android/one-click-tethering-solution-for-att-and-rogers-one-x/

http://forum.xda-developers.com/showthread.php?t=2595190

N4 ATT APN Settings

Nexus 4 on 3gb $30 AT&T Plan 

Source:  http://forums.androidcentral.com/google-nexus-4/226814-anyone-activated-nexus-4-att.html

Option #2. http://m.imgur.com/a/buRB4

Doorbell w/ WiFi & Camera

"Skybell wants to replace your doorbell" http://feedly.com/e/AHM6gUPC