Ivy League universities receive thousands of admissions applications each year but admit only a small percentage. Although the schools do not set minimum GPAs for applicants, you can judge by the averages of currently admitted students. At Stanford, for example, over half of students admitted for Fall 2010 had a 4.0, with 84% having over a 3.7.
For students who don't have the GPA to make the cut at Cornell or Harvard, the mid-level colleges might be a better choice. Schools such as Indiana University and the University of California give preference to students with at least a 3.0 GPA.
Students who have lower than a 3.0 may need to apply to community colleges. These schools typically admit any student, although some may be admitted conditionally. Students can sometimes complete core courses at a community college and then transfer to a higher-tier school.