The following resources have been found useful in the study of Senate procedure and debate. At left as well as in the list below, the link will either load the resourse as PDF, or take you to the online source.

A Manual of Parliamentary Practice. For the Use of the Senate of the United States. – Thomas Jefferson
In search of a way to augment the existing Senate rules, Jefferson looked to the British system as a model. Though the corruption and abuse then evident in the British government offended him, he appreciated the House of Commons' rules because he found that they helped elicit a true sense of the entire body's wishes. Always wary of the power of majorities, he underlined the importance of procedure as "a shelter and protection to the minority, against the attempts of power."
A Century of Lawmaking for a New Nation: U.S. Congressional Documents and Debates 1774–1875
This is the gateway to the Library of Congress hosted-collection of the journals and debates of both houses of Congress, and is a frequent reference for knowledgeable senators.
How the U.S. Vice President Works
A simple-enough explanation that even a child can comprehend, the site describes the limited power of the presiding officer of the Senate.
The President of the Senate's Role in the Legislative Process
Another simple explanation, as provided by the corporate Senate.
Vice President of the United States (President of the Senate) – Chapter 2: Constitutional Origins & Structural Changes; Vice-Presidential Duties
Within chapter 2, the subsection on Vice-Presidential Duties explains simply the importance of the separation of powers doctrine and the limitations imposed upon the President of the Senate. The balance of the article is also well written and informative.
The Legislative Process on the Senate Floor: An Introduction – Valerie Heitshusen, Congressional Research Service
An excellent introduction to legislative procedure and the quirks adopted by the corporate Senate which streamline the same. Of particular interest recently is the explanation that the President of the Senate may not pick and choose whom to recognize.