Purdue University Online Writing Lab
Provides information, handouts, and exercises for students and instructors on a variety of writing topics. Includes a section on Internet research.
A fun source of sometimes downright silly—but challenging—interactive exercises, handouts, and lessons about grammar, mechanics, and sentence-level skills.
University of Wisconsin-Madison Writer's Handbook
Covers major documentation styles—including APSA, APA, Chicago/Turabian, CBE and MLA—as well as thesis and dissertation guides.