CareerOneStop -- is sponsored by the U.S. Department of Labor. This site also offers help preparing resumes and sample documents.
Purdue University's Online Writing Lab -- has links to job searching resources like how to read job ads, writing a resume and sample documents.
Resume Resource -- helps in preparing a resume, but also offers help with letters of recommendation. Check out the long list of power verbs to use in your resume.
A Student's Guide to Writing a Resume – provides links and useful information on preparing a cover letter and resume for recent college graduates