I contributed a little something to my friend Bobby's blog about the use of cloture in the US Senate, and I discovered the wonders of WikiPedia, “the free encyclopedia” on the Internets.
Two good links. First, the entry on the United States Senate provides a very clear and understandable of the Senate, its powers and its personalities.
Second, and a more topical area of information, is the entry relating to the Cloture Rule (adopted by the US Senate in 1917).
Interestingly, a reference to another entry called the Nuclear Option is made (one I've not heard of), which suggests that by declaring the filibuster unconstitutional (a motion made by a senator would be required to enable this ruling), only a simple majority is needed to uphold the decision of the “chair.” Definately worth reading about this, as well as a very good overview of the current situation that is happening (note that there are less than 10 nominees being “held up”, and over 210 that have been confirmed).