PB
Addicted to ArboristSite
Here is a link to tree identification in the Northeast. It is specific to Maine, but many trees are found further south and west. It is 114 pages for free, or you can order the centennial edition for around $10. I have to say this is the best tree identification book I have found. The centennial edition has great photos and other identification information. Hope this helps someone.
http://www.maine.gov/doc/mfs/pubs/ftm/ftm.pdf
http://www.maine.gov/doc/mfs/pubs/ftm/ftm.pdf