Lively day for Fast and Furious
First, Obama (not Holder) invokes executive privilege over the Fast and Furious papers. Then, Issa's Committee holds Holder in contempt of Congress. The next step is a vote by the House (it doesn't have to go to the Senate). After that the charge is referred to DoJ. If it (surprise!) refuses to press charges, I believe the House appoints one of its members to press charges in its name.
UPDATE: Ken Klukowski has written a law review article on the procedure for bringing a contempt of Congress charge; while I can't find it online, I can find his article on it at Breitbart.