Senator Barack Obama is thinking about running for president in 2008.

He tells media sources... he can no longer stand by the statements he made after his election two years ago, and earlier this year, that he would serve a full six-year term in the Senate.

Obama, speaking on "Meet the Press," said he's "thought about the possibility" of running because of the response he's been getting over the past several months.

He says he won't make a decision until after the November elections.

He was largely unknown outside of Illinois until his widely-acclaimed speech at the Democratic National Convention in 2004.

And he's been seen recently as a viable centrist candidate for president, now that former Virginia Governor Mark Warner has announced he's out of the race.

As for his lack of experience, Obama says, "I'm not sure anyone is ready to be president before they're president."