Harvard: http://www.math.harvard.edu/graduate/index.html#qualifying

Berkeley:http://math.berkeley.edu/index.php?module=documents&JAS_DocumentManager_op=viewDocument&JAS_Document_id=6

Stanford: http://math.stanford.edu/quals/oldquals.htm

UCLA: http://www.math.ucla.edu/grad/handbook/hbquals.shtml

U of Michigan:http://www.math.lsa.umich.edu/graduate/qualifiers/index.html

John Hopkins University: http://www.mathematics.jhu.edu/new/exams/syllabus_exams.htm

U of Wisconsin Madison:http://www.math.wisc.edu/graduate/quals.htm

UCI:http://www.math.uci.edu/graduate/exam.php

Putnam examination: http://www.math.niu.edu/~rusin/problems-math/

Georgia Institute of Technology, For math:

http://www.math.gatech.edu/academics/graduate/sample-comprehensive-exams

for aco:

http://www.aco.gatech.edu/descript.html#Comprehensive%20Examination

2010 exam

2011 exam