links to rock ID sites (some state what types of rocks are likely to contain fossils).

http://www.rocksforkids.com/RFK/identification.html
http://geology.about.com/library/bl/blrockident_tables.htm
http://www.paleocurrents.com/castle_rock/gallery/master_index.html
http://jersey.uoregon.edu/~mstrick/MinRockID/RockID/RockIDChart.html

The best pics for rock ID are:
http://www.pdac.ca/miningmatters/teachers/resources-rock.html