Here's an early sign this wiretap scandal is playing to a different script than previous scandals. Five Senators delivered a letter on December 19th to the chairmen of the Judiciary and Intelligence committees asking for joint hearings on the issue of Bush's warrantless wiretaps.
On the Judiciary side Arlen Specter, who is not a Bush loyalist, is probably willing to get started right away. Pat Roberts, who is the Intel Committee chair and a shameless Bush bootlicker, will almost certainly refuse. However, as noted at the linked page, since there are five committee members requesting the meeting, they can call it themselves after seven calendar days, which would mean next Tuesday (Monday is a federal holiday.)
These hearings would be a really big deal, though of course any impeachment proceeding would have to originate in the House.