How important are the SAT exams to colleges?

I, honestly, have excellent grades in school, have many extracurricular activities that I've been dedicated to for three years, community service hours and excellent recommendations from my teachers. I'm taking the SAT this Saturday and I'm not the greatest test taker. That will probably affect my score (I got a 1570 on the PSAT) and I was just wondering how much do colleges look at the SAT?