Kennedy writes for Court. Affirmed in part, reversed in part, and remanded. More coming.
From SCOTUSBlog’s reporting, it sounds like the most likely scenario occurred:
Austin and McConnell (that part dealing with corp. spending limits on “electioneering communications”) are overruled on a 5-4 vote (liberal/conservative split). Disclosure rules are upheld.
Lyle reports that Justice Stevens’ dissent is 90 pages.
UPDATE: The total of opinions is 183 pages. In case the Supreme Court’s server is busy, you can read the opinion here.