Try your local book store or amazon.com for starters.
On the web type "salem witch trials" into any search engine
Go to
http://freepages.genealogy.rootsweb.com/witchtrialancestors
http://www.law.umkc.edu/faculty/projects/ftrials/salem/SALEM...
http://etext.lib.virginia.edu/salem/witchcraft/index.html
http://etext.lib.virginia.edu/salem/witchcraft/texts/

Those should help get you started

Happy Hunting!
Lisa