The Fossil record:

http://www.agiweb.org/news/evolution/fossilrecord.html

http://atheism.about.com/od/evolutionexplained/a/FossilRecordEvolution.htm

http://carnegiemuseums.org/cmag/bk_issue/2000/marapr/feat7.html

http://www.actionbioscience.org/evolution/benton.html

Image: fossils over time:

http://www.agiweb.org/news/evolution/figures/newscallops.jpg

Image: fossils over time:

http://whyevolutionistrue.files.wordpress.com/2009/03/fish.jpg

Isotopic dating

http://www.agiweb.org/news/evolution/datingfossilrecord.html