MOUNTAIN VIEW, Calif. — Look who’s calling the kettle black.

Last year Google denied Microsoft’s claim that the search giant’s proposed acquisition of online ad company DoubleClick would cripple competition for Internet advertising. Now Google co-founder Sergey Brin is suggesting that Microsoft’s proposed $44.6 billion takeover of Yahoo (YHOO) would monopolize the Internet.

“The Internet’s evolved from open standards,” said Brin when an Associated Press reporter asked him about Yahoo Thursday at a press conference at the Googleplex. “When you start to have companies that control operating systems and browsers, they tie up top websites. I think that’s unnerving.”

Earlier this month, David Drummond, Google’s (GOOG) senior vice president for corporate development and chief legal officer, argued in an official Google blog post that Microsoft-Yahoo merger could quash innovation on the Internet.

Brin, who did not mention Microsoft by name, made his comments as Google unveiled the finalists competing for the Google Lunar X Prize, a $30 million competition to put the first commercial rover on the Moon.

“When you think about the budgets to make movies or race sailboats…it occurred to me that if we should be sponsoring things, it should be for new discovery in ambitious ways,” Brin said. “When I found out what it would take to get a rover on the Moon, I was shocked at how this incredible space for human discovery was relatively low-cost.”

Southern California Selene Group, one of ten finalists for the Lunar X Prize, estimates that it can send a private rover to the Moon for about $20 million, or about a tenth of NASA’s budget. It says it has the resources to complete the mission within two years. Teams have six years to land a rover on the Moon, let it roam for 500 meters, and send video images and data back to Earth.

Other finalists include Frednet, which will use open-source technology to build a rover, and a Romanian aeronautics team.