The Occuptional Outlook Handbook, published by the United States' Bureau of Labor Statistics, provides a ton of current, authoritative information about pretty much any career you can imagine. Choose one of the broad categories linked on the left, then a specific career category, for information about the nature of the work, training that may be necessary to land a job, the projected job outlook, and projected arnings.
Much like the Occupational Outlook Handbook, O*Net provides current information about most occuptations, including skills and abilities needed, working activities, working values, and salary information. O*Net's partner site, My Next Move, leads you to career options and information about careers based on anything you type. You can describe your dream career, browse by various industries, or fill out a brief survey that will profile your interests.