Woe is I: The Grammarphobe's Guide to Better English in plain English
PE1112 .O28 (Reference Section)
A funny, down-to-earth approach to common grammar issues.
A Writer's Reference
PE1408 .H2778 (Reference Section and Circulating Collection)
A classic handbook covering grammar, style, punctuation, and mechanics.
Elements of Grammar
Concise and comprehensive explanations of punctuation, capitalization, the parts of the sentence, words often confused, foreign words and phrases, numbers, signs and symbols.
Step-by-step guide to spelling, punctuation, and grammar usage.
501 Grammar and Writing Questions
Questions and answers about punctuation, grammar, and sentence structure.
Some history mixed with grammar how-to's--read this if you want to appreciate punctuation!
A quick reference for grammar issues
An excellent guide to basic grammar and usage
Practice your grammar!
A searchable database of common grammar problems
Rules, examples, quizzes, and videos about grammar and punctuation
A guide to grammar written by a professor at the College of DuPage (scroll down to "A Review of the Structure of Modern English Grammar")
Because it's awesome