Purdue University's Online Writing Lab
The Online Writing Lab (OWL) at Purdue University offers writing resources and instructional material, and they provide these as a free service of the Writing Lab at Purdue. Students, members of the community, and users worldwide will find information to assist with many writing projects.

MIT Writing Center: Resources for Writers
Includes advice on understanding an assignment, the writing process (prewriting, drafting, revising, editing), introduction strategies, elements of specific types of documents, and grammar.

Writing & Grammar: Plough Library Subject Guide
This guide from Plough Library includes lists of helpful reference books, electronic databases and websites to assist you in your writing.