Here is an informative instructional video for completing the Common Application for college admission. Most colleges accept the Common Application in applying to college, but not all—be sure to check with whatever institution you’re applying.
This application process is accepted by a little over 500 colleges as of 2013-2014, and the admission process looks at the whole application, such as the essay, extra-curricular activities and letters of recommendation, not just grades and academic achievements.
One large benefit in this process is that the application allows for applying to multiple schools at once. Participating schools include Yale, Harvard, Columbia, Cornell, Boston College, and many others.