Was there ever any doubts about this?
Obama takes 1st step in presidential bid
Obama announced his intentions to file a presidential exploratory committee on his Web site. He said he would announce more about his plans in his hometown of Chicago on Feb. 10.
"I didn't expect to find myself in this position a year ago," Obama said in a video posting. "I've been struck by how hungry we all are for a different kind of politics. So I spent some time thinking about how I could best advance the cause of change and progress we so desperately need.
"The decisions that have been made in the past six years have put our country in a precarious place," he said.
[update]There was speculation on MSNBC that Hillary Clinton may have cancelled her plans to announce her running today because shortly after Obama's announcement she postponed/cancelled a news gaggle she had planned.