This just in from the White House:
At 4:15 p.m. ET, the president "will convene a news conference ... in the Eisenhower Executive Office Building at the White House."
Our original post, headlined "Obama Likely To Hold Short News Conference Today":
The time isn't yet set and White House spokesman Robert Gibbs says the news media won't get much warning, but he expects President Obama will hold a brief news conference later today.
It's expected to happen shortly after the Senate votes this afternoon on ratification of the New START missile pact with Russia.
"That's my hope," Gibbs just told reporters at the White House, when asked about whether they will be getting a chance to question the president today.
We'll live-blog the back-and-forth when and if the news conference happens.
Update at 11:01 a.m. ET. A little more on the timing:
"Our hope would be that we could do something sort of mid- to late-afternoon," Gibbs just said.