I applied through a recruiter. The process took 5 days. I interviewed at US Marine Corps (Colorado Springs, CO) in May 2009
Interview
It is an intense process. They review every aspect of your life. Drugs, jail, employment, lack of employment. They recruit straight out of college and high school, and the higher your scores, the better. I scored very high so I was not limited in any way. It can be as fast as a few days or as long as a few years.