Technical Writing and English Usage
The Craft of Scientific Writing (writing guidelines for science and engineering students)
American Institute of Physics (AIP) Style Manual (THE authority for physics papers)
Chart of Proofreader's Marks (from AIP)
Oxford English Dictionary ("the definitive record of the English language" according to them, but note that US English spelling and usage may differ; we colonials have our own rules)
William Safire's Rules for Writers
Not available online, but highly recommended for your library if you're serious about writing well:
The Elements of Style, William Strunk, Jr. and E.B. White, 4th ed. (New York, Longman, 2000).
Garner's Modern American Usage, Bryan A. Garner (Oxford, Oxford University Press, 2003).
The Careful Writer, Theodore Bernstein (New York, Atheneum, 1965). Old but timeless.
TeX and LaTeX Resources
LaTeX Project (includes a searchable "bugs" database)
Comprehensive TeX Archive Network (provides the most complete and up-to-date TeX-related software)
Visual Display of Quantitative Data
Graphing Resources (from North Carolina State University and the National Science Foundation)
"Introduction to Refereeing" (from the Institute of Physics)
University Library resources page Note that the University Library no longer supports RefWorks
Comparison of reference management software systems
Citing Sources and Avoiding Plagiarism
Plagiarism.org comprehensive resource that defines what constitutes plagiarism and helps you avoid inadvertent plagiarism
The Plagiarism Checker free site to detect plagiarized text