Career Interests Game
This is a game designed to help you match your interests and skills with similar careers.

MAPP (Motivational Appraisal of Personal Potential) Assessment
An assessment that is designed to guide, motivate, and empower people to achieve your greatest educational and career potential.           

Occupational Outlook Handbook
Courtesy of the Bureau of Labor Statistics, the Handbook includes information on 250 occupations including the nature of the work, training, job outlook, and earnings.

Personality Type
A personality assessment based on the Myers Briggs Type Indicator instrument (MBTI).  

Planning a Career 
Find out how to choose a career and how to reach your career goal.

Quintessential Careers
This site is a resource in a number of areas, including cover letters, resumes, marketability test, and job links.

The Temperament Sorter II 
A personality questionnaire that reveals possible temperaments.

TypeLogic
For more information on your personality type.

Sites on skills testing:

Test Prep Review
Free practice tests, help with reviewing, prep time, and prep resources.

College Board
A testing organization.  There are guides to 150 college majors and career paths.

Educational Testing Service
Various methods of preparing for aptitude tests. Details of services, etc.

The Princeton Review
One of the top review and testing centers, this site details their services and offers some interactive tests for the GMAT, LSAT, and so on.

Psychometric-success.com
This site is aimed at providing student job seekers with the practice material they need to pass psychometric job selection tests. It has over 100 pages of information on psychometric and aptitude tests, free downloadable practice tests and a free eBook which gives expert advice on how to approach aptitude tests.