Useful links with writing advice
OWL -- The Purdue University Online Writing Lab
Offers many resources: Writing and Teaching Writing, Research. Grammar and Mechanics, Style Guides, ESL (English as a Second Language), Job Search and Professional Writing
The Writing Place Online Writing Resources
Northwestern's Writing Place provides links to sites that offer advice on starting a paper, conducting research, editing a paper, citing sources, and many other topics.
The Writing Center of the University of North Carolina
Handouts discussing a broad range of writing topics: brainstorming, organizing, editing, writing in different disciplines, and many more