It appears that the Senate will move try to tackle two legislative priorities at once, as soon as it finishes the tax-cut bill: 1) the New START treaty and 2) the government spending bill. This information comes from a Democratic and Republican source.
The two-at-once procedure is known as "dual tracking."
It essentially means trying to pass two different bills at the same time, alternating debate and votes on the floor.
Expect to hear more about it from Senate Majority Leader Harry Reid at his news conference this afternoon.