App that shows service provider (ATT/Verizon/Sprint) upon call?

[NovemberWhiskey]

Is there an app that shows a caller's phone carrier (e.g. ATT/Verizon/Sprint) when they call or just checks all your contacts and puts that in their contact info?

I am trying to find out who is mobile-to-mobile because those minutes are free, but want an easy way to find out if someone else is ATT.

 

[FXT 1]

Not sure about an app, however this might help.

http://www.wireless.att.com/cell-phone-service/mobile-to-mobile/lookup.jsp

http://www.verizonwireless.com/b2c/LNPControllerServlet?path=lnppromo1

Just a 3 second google search. Didn't bring up Sprint however.