Jim Ryan, former head of data services for AT&T Inc, worked for two years to clinch the phone company’s deal as the only other retailer of iPhone besides Apple. Then he quietly left AT&T two months before iPhone’s grand entrance on June 29.

Ryan, who now heads mobile messaging company Mobile Campus, said he left “one of the cooler jobs in the country if not the world” because he wanted to go work for start-ups before iPhone exploded onto the scene and made it difficult for him to leave for another year when Reuters caught up with him on Friday.   

How big will iPhone be?
“I don’t think that ultimately iPhone takes over the world.” (He predicted that the $500 and $600 phone will be a “small to reasonable” percentage of AT&T phone sales.)
    
Will it have big influence?
“I think it helps set the bar … You’ll see real competition in the phone market.”
    
Did AT&T give up too much in replacing its typical data service offering with handpicked Apple services on the phone?
“The thing that I do really take pause with … is stories about how Apple’s getting one over on AT&T. You really have to take a step back and look at the tremendous value AT&T is getting out of this.”
    
He compared the Apple agreement to the way carriers work with Research In Motion, whose Blackberry is loved for Rim’s mobile e-mail service rather than wireless company’s data offerings and said wireless carriers should be more open to these kinds of partnerships.
    
“You start from that premise and you really want to delight your customer and you try not to make ego part of the equation you’re going to give them the best service you can … If there are people who want an Apple experience on their phone why shouldn’t they.”
    
Speaking of egos, why could Ryan not stick around another year to usher in the most famous phone in history?
“That seemed like a bridge too far.”

Please check out Reuters’ ongoing coverage of the iPhone launch here.