March Madness on iPhone is turning out to be a slam-dunk for CBS TV advertisers.

Advertisers for CBS broadcasts of the NCAA men's basketball tournament now underway are getting a bonus: Their ads show up in games viewed on iPhones via a $4.99 CBS application.

Coke, for one, is happy. "It's an innovative iPhone application that gives us an additional way to connect Coke Zero with NCAA fans," says spokeswoman Susan Stribling.

Marketers didn't know about the iPhone bonus when they made their TV ad buy. The network and Apple sank one at the buzzer, announcing just days before the tournament began an application to make game video available.

It is one of more than 25,000 apps, which provide the phone with specific added capabilities or services, available for the iPhone (including one for USA TODAY). Advertisers increasingly have become involved, including with apps of their own.

CBS has streamed the games on mobile devices since 2007 on the TV subscription services used by AT&T and Verizon mobile customers. The $15-a-month mobile TV service is through Qualcomm's MediaFLO. This year CBS is providing all the games vs. just 26 last year.

But the iPhone app is the first stand-alone option, and it adds some fun features.

"One of the really cool things you can do is pull up stats, and it shows up as a transparent overlay while the game is on," says Jeff Sellinger, general manager for CBS Mobile.

Advertisers' exposure on the mobile stream has been a free bonus so far, but that could change after this year. Greater mobile distribution should boost the out-of-home audience numbers CBS can tout for advertisers -- and put a price tag on.

"As the audience grows on mobile, we'll be in a position to start talking to advertisers about the rest of these numbers, and we can finally quantify them,"...