During an interview with Microsoft CEO Steve Bullmer during Mobile World Congress 2010 in Barcelona, when asked the question whether Microsoft’s Bing search engine will replace Google on the iPhone, Bullmer smiled and said “I won’t comment either way.”

Bullmer was speaking with Reuters at Microsoft’s launch of Windows Phone 7 Series which apparently they hope will drag back lost market share, and Bullmer remarked that Windows Phone 7 Series would distinguish Microsoft smartphones from anything else available on the market.

The Microsoft CEO also stated “Look at the user experience around these new phones, and they’re really quite different from anything that lives in the smartphone world today.”

On the subject of if Microsoft would ever purchase a rival such as BlackBerry, Ballmer responded “the word ‘ever’ is a big word, but I certainly don’t feel like that’s the right strategy for us today.”

So it looks like Ballmer didn’t give anything away on the iPhone gaining Bing front, but I’m sure the speculation whether Google will lose the iPhone and Bing gain it will continue for some time.