Roger McNamee is very bullish on the iPhone. “It’s the most exciting thing in years,” said the longtime Silicon Valley investor. “With Apple’s identity, I think it will be spectacularly successful.”

This, of course, is an interesting product for McNamee to cheer for. Because last week, Elevation Partners, the high-profile private-equity firm that counts McNamee and also U2 singer Bono among its partners, sunk $325 million of its $1.9 billion fund to buy one-quarter of Palm. The maker of the Treo smart phone, of course, could take a big hit if the iPhone lives up to its hype and dominates the market for high-end, heavily featured mobile devices.

Still, McNamee, whom I interviewed here a few weeks ago, keeps reeling off a bunch of non-Palm smart phones he loves–he tries all of them and often wears several in high-tech style (not!) on his belt.

“I loved the BlackBerry Pearl, and Motorola and Samsung have done some cool stuff and I liked a lot of the features on Helio’s new Ocean,” he said. “And that iPhone will probably be a huge hit does not bother me at all, because this is not a zero-sum game.”

McNamee’s theory is simple–although only a small percentage of all phones sold are smart phones, he expects that to eventually be 100%, because, he posits, “in the end, what matters is what you carry on your body.”

So, even if Palm, which is a small player compared to competitors like Nokia and BlackBerry-maker Research in Motion, comes in third or fourth, that, said McNamee, is “not so bad.”

Not that he expects that kind of also-run status for Elevation’s investment. So to help buoy Palm, along with the big pile of cash, he will also join the board and has brought in two former Apple executives, too–former CFO Fred Anderson and former hardware head (think iPod) Jon Rubinstein.

Anderson is also a partner at Elevation and Rubinstein will serve as executive chairman and also run product development at Palm.

“We offer committed value insight and want to be a partner to management and shareholders, but, most of all, we want to help foster a culture of radical innovation,” said McNamee. “I am a huge believer that you have to be able to experiment to be able to innovate and you even need permission to do so.”

The $325 million buys a lot of permission, of course, and was, said McNamee, an unexpected opportunity. The deal was hatched about seven months ago, when McNamee was called by Palm CEO Ed Colligan, who was seeking good advice about Palm’s options.

While McNamee admits he was not a regular user of Palm products, although he did try them out, he was impressed by Palm’s years of large accomplishments compared to its size.

Nonetheless, the company has been under a lot of pressure to perform better and also do something to lift its lagging stock price. With a huge hoard of cash and even the possibility of being sold to a bigger player, Palm was receptive when McNamee proposed a different tack.

Under terms of the new restructuring deal, still to be approved, Palm’s existing shareholders will get almost $1 billion in cash (the money from Elevation, some new debt and cash from Palm’s kitty) to drop their stake to 75%.

What McNamee said he is buying is a company great at both software and also hardware, which he thinks need to become even more tightly integrated to make products seamless.

“All the really successful products are like that, because someone has to take responsibility for the whole thing,” said McNamee. “And product change has to be the rule rather than the exception… with the goal, of course, to have an incredible device everyone wants to own.”

That might be the goal, but Palm’s latest device, unveiled at D5 last week by Palm’s co-founder and top product guru Jeff Hawkins, called the Foleo, was not well received.

The “phone companion”–which sounded naughty to me when I heard it described thus–was thought by many I spoke with to be too large and not feature-rich enough to be useful.

McNamee understands this, but said Foleo was only a starting point. “It is a good thing for a company to try new form factors, and Foleo is an excellent first step,” he said, even though he admitted the device probably does not represent a very big market.

But he liked the effort involved in its conception.

“Innovation is not a matter of always hitting a bulls-eye on the first shot,” he said. “So I hope we’re there to help Palm be able to keep trying.”