Initially, news reports said that Giffords was killed (shot point-blank to the head), but they now report that she is alive, in "very critical condition", and still in surgery.
Here's a live news feed from local television [if the video does not work, the direct link is here]:
Several of the victims have died so far, including a congressional staffer.
UPDATE: Reports from law enforcement say that a federal judge is among the wounded. The gunman has been apprehended.
UPDATE 2: A doctor reported at a press conference that a young child died at the hospital, and that Rep. Giffords has made it through surgery. He is optimistic about her recovery.