Renaissance architecture:
http://www.greatbuildings.com/types/styles/renaissance.html
http://www.Tulane.EDU/lester/text/Renaissance/Italian.Renaissance/Italian.Renaissance.html
http://tqjunior.thinkquest.org/3786/renaissance_.html?tqskip=1
http://architecture.about.com/arts/architecture/msubp-ren.htm?once=true&

Art and architecture:
http://www.wsu.edu/~wldciv/brians_syllabus/40.html
http://www.infoplease.com/ce6/ent/A0841518.html
http://historymedren.about.com/homework/historymedren/library/who/blwwartdex.htm

-- Watch out! Some people on this site are medieval, not renaissance!

Authors:
http://www.luminarium.org/renlit/ -- Great Site! Has almost all the information you will need!

Art:
http://www.geocities.com/Paris/Gallery/2892/renaissance.html
http://witcombe.sbc.edu/ARTHLinks2.html
http://www.infoplease.com/ce6/ent/A0841518.html

Mathematics:
http://www.britannica.com/eb/article?eu=118177&hook=536244#536244.hook
www.kn.pacbell.com/wired/fil/pages/listmathematch.html

Inventions and Inventors:
http://www.scarboroughrenfest.com/school_days_inventions.htm
http://www.mce.k12tn.net/renaissance/inventions.htm

MLA Style:
http://www.hcc.hawaii.edu/education/hcc/library/mlahcc.html