DowJones is reporting that the FCC is looking into the reason for the Google Voice application being rejected for the iPhone. They've sent letters to Google, Apple and AT&T seeking answers as to why the VOIP (voice over the internet protocol) app was rejected. The inquiry is part of a larger investigation to handset maker and carriers having exclusive deals with each other. The iPhone is sold exclusively on AT&T in the United States.

Personally, when I heard that the Google Voice app was rejected, I thought it was a giant publicity stunt by Apple and Google to show that they're not really anticompetitive. The FTC recently launched their own investigation into the ties between the two.

For its part, AT&T says it has nothing to do with the approval or rejection of apps. But they might want to revise their official answer, since they did reject Slingbox.

AT&T is likely concerned about two things - iPhone customers using VOIP instead of their minutes, plus the use of bandwidth is becoming a problem for the carrier (according to them).

Google Voice can still be used with an iPhone, but it requires calling an extra step or two than a normal phone call.

Stay tuned for this unfolding drama.