Well, Congress was notified of the impending raid, but by the CIA, and apparently without White House permission. The DOJ for example (including the AG) was not notified until after the fact. Four CIA and Pentagon lawyers were basically the legal team consulted beforehand, and they advised not notifying Congress of the pending/ongoing operation. But it turned out, Congress had been notified without White House permission by the CIA.
Mr. Preston wrote a memo addressing when the administration had to alert congressional leaders under a statute governing covert actions. Given the circumstances, the lawyers decided that the administration would be legally justified in delaying notification until after the raid. But then they learned that the C.I.A. director, Leon E. Panetta, had already briefed several top lawmakers about Abbottabad without White House permission.
However it's not clear just from that what level of notification was provided. I.e. it's not clear if the actual timing was revealed when the raid was to start or had started.
Feinstein who was then on the Senate Intelligence committee confirmed this in general terms, but again details of what she knew and when are lacking:
Sen. Dianne Feinstein (D-Calif.), chairman of the Senate intelligence committee:”Bin Laden is responsible for the attacks of 9/11 and has been the head of al-Qa’ida and inspirational leader of extremism for more than a decade. His death presents an opportunity for a new and better day if the will is there. I truly hope this will be a turning point in our efforts to defeat global terrorism. ... I was notified on Sunday of the strike and have been briefed in the past about intelligence on bin Laden’s whereabouts. It has been a very impressive CIA operation and they deserve praise.”
"Sunday" was May 1, 2011, but with the time difference between US and Pakistan it's hard to tell when she was told what just from that.
CNN summarizes the events in an article today as
Before the Osama bin Laden raid, key members of Congress knew about surveillance of the al Qaeda leader and knew something might be coming, but did not know specific details as the raid was happening.
CNN links to a rather lengthy CRS document in support of that. I haven't gone through all of it, but obvious bit regarding notification(s) is this
The chairmen of the House and Senate intelligence committees have stated that they were briefed
on OBL’s whereabouts during the past few months including, according to Representative Mike
Rogers, Chairman of the House Intelligence Committee, some details regarding the Abbottabad
compound. The Senate Majority Leader, Senator Harry Reid, has also indicated that he had been
briefed on the plans to confirm OBL’s location and take action. Chariman Rogers indicated that
the entire “Gang of Eight” had been briefed on the plans although not all were briefed at the same
time. The Gang of Eight refers to the eight Members of Congress (the Speaker, House Minority
Leader, the Senate Majority and Minority Leaders, and the chairmen and ranking members of the
two intelligence committees) who, by statute, must be advised of Presidential Findings of covert
actions (along with other members of the congressional leadership as may be included by the
President). A finding is an official determination by the President that a specific covert action is
in the national interest.
A covert action is an activity to influence political, economic, or military
conditions abroad where the role of the U.S. will not be apparent or acknowledged publicly.
PBS News Hour interview on May 3, CIA Director Leon Panetta stated, “this was what’s called a
‘Title 50’ operation, which is a covert operation, and it comes directly from the President of the
United States who made the decision to conduct this operation in a covert way.” He added that,
consistent with Title 50, he commanded the mission but it was carried out by Vice Admiral
William McRaven, the commander of the Joint Special Operations Command.
For additional background on covert action notification issues, see CRS Report R40691, Sensitive
Covert Action Notifications: Oversight Options for Congress.
So there is some legal justification/requirement for what Panetta did in terms of notifications.
The same document raises these questions (but as far as I can tell doesn't answer them):
In retrospect, was congressional notification overly restrictive? When was the
written Presidential Finding (required by 50 USC 413b(a)(1)) reported to the
several members of the Gang of Eight? Has the written Finding now been shared
with all members of the two intelligence committees?
Did the operation necessarily constitute a cover[t] action? Could it have been
considered a traditional military activity? Was the role of the CIA Director essential to carrying out the operation? Could it have been carried out by the
Secretary of Defense? Other than the role of Director Panetta what was the
contribution of CIA officials to carrying out the raid?
Should there be statutory provisions requiring that the Armed Services
committees (or their respective leaderships) be advised of activities such as the
I'm guessing those questions have remained somewhat unresolved. Almost certainly there has been no substantive change on the last one.