The filibuster is an emergent property of the US Senate not having rules to limit the amount of time spent on debate, and it's valuable because it keeps majorities from completely over-ruling minorities. The particular issue is federal judges (with the Supreme Court likely to be an issue in the forseeable future), but even if you're fond of the current administration, you should consider the possibility that you might want some limits on any future administration you don't like as much.
Susan Collins (ME) - (202) 224-2523
Mike DeWine (OH) - (202) 224-2315
Judd Gregg (NH) - (202) 224-3324
Chuck Hagel (NE) - (202) 224-4224
Dick Lugar (IN) - (202) 224-4814
Lisa Murkowski (AK) - (202) 224-6665
Pat Roberts (KS) - (202) 224-4774
Gordon Smith (OR) - (202) 224-3753
Arlen Specter (PA) - (202) 224-4254
John Sununu (NH) - (202) 224-2841
John Warner (VA) - (202) 224-2023
ETA: It's been confirmed by a call to her office that Olympia Snowe (ME) - (202) 224-5344 has not confirmed her vote to continue the use of the filibuster. Please consider her to be added to the list of people to call.
I called Arlen Spector, and was only on hold for a few minutes.
Wikipedia--recommended, including a section on an inventive high-tech Canadian filibuster.
List of Senators.
This country's planted thick with laws from coast to coast--man's laws, not God's--and if you cut them down--and you're just the man to do it--d'you think you could stand upright in the winds that would blow then? Yes, I'd give the Devil benefit of law, for my own safety's sake. ---Robert Bolt, _A Man for All Seasons_