These are examples of the recommendations and requirements from some well known universities:
Georgia Institute of Technology
"Two courses in one language emphasizing speaking, listening, reading, and writing are required."
(from http://www.admiss.gatech.edu/freshman/#reqs)
Harvard University
"You should leave secondary school knowing at least one foreign language well enough to read it easily and pronounce it acceptably. Knowing a foreign language enables you to enter another culture and to understand its ideas and its values. A fundamental aspect of language-learning must be a grasp of vocabulary and syntax that allows you to read novels, plays, poems, and magazines, with as much of a native speaker's comprehension as possible. We have found that students who have mastered a foreign language before they come to Harvard take more language courses here than those who have not. Indeed, these students often embark on the study of languages not commonly taught in American secondary schools.
Many secondary school students take a smattering of several languages – for example, Latin for two years, French for a year, and Spanish for a year. When it is too late, they realize that they cannot read or speak any of these languages well. We urge you to try to study at least one foreign language and its literature for four years. Continuity of study is important, too, because a "year off" from a language can be a real setback. Once you are comfortably fluent, you will possess that language – and better appreciate the culture it has shaped – for the rest of your life."
(from http://www.admissions.college.harvard.edu/prospective/applying/college_prep/index.html#language)
MIT
"Two years of a foreign language."
(from http://www.mitadmissions.org/topics/before/recommended_high_school_preparation/index.shtml)
Stanford University
"Three or more years of the same foreign language. Your study of a foreign language ought to include the development of four basic skills: reading, writing, speaking, and listening comprehension."
(from http://www.stanford.edu/dept/uga/applying/1_2a1_acaprep.html)
UCLA
"2 years required, 3 years recommended - Two years of the same language other than English. Courses should emphasize speaking and understanding and include instruction in grammar, vocabulary, reading, and composition."
(from http://www.admissions.ucla.edu/Prospect/Adm_fr/fracadrq.htm)
University of Illinois, Main Campus
"2 years of one language."
(from http://www.oar.uiuc.edu/future/apply/requirements_freshman.html)
University of Michigan, Main campus
"Students entering the College of Literature, Science, and the Arts are strongly encouraged to take four years of language study, but only two years are required for admission."
(from http://www.admissions.umich.edu/prospective/prospectivefreshmen/admissionreq.html)
Williams College
"A challenging and well-balanced program of study ideally should include: a full four-year sequence in English and mathematics; study of one foreign language for three or, preferably, four years."
(from http://www.williams.edu/admission/apply_prepare.php)