Koriwhat is correct in suggesting you can get into college without acquiring a high school diploma. You can get a GED, go to community college, and matriculate that way.
However, koriwhat is absolutely wrong to suggest that a high school diploma has no use value in this country. Individual cir stances differ, of course, but the person with the high school diploma is likely getting into better schools than the person with the GED. Additionally, they're likely entering the work force sooner and with more attractive credentials. Completing high school is, technically, not a requirement for living a relatively successful life (meaning finding a job and the means to support yourself). By dropping out, though, you're absolutely putting yourself at a disadvantage. To suggest otherwise is ignorant and smacks of desperate rationalization.