CAN-SPAM Act: A Compliance Guide for Business

FTC www.ftc.gov/spam

U.S. CAN-SPAM ACT 
http://thomas.loc.gov/cgi-bin/query/z?c108:s.877.enr:

U.S. State by State laws regarding Spam 
http://www.ncsl.org/programs/lis/legislation/spamlaws02.htm

Google GMail Rules 

http://www.google.com/mail/help/bulk_mail.html 

Hotmail Anti-Spam policy 

http://privacy.microsoft.com/en-us/anti-spam.aspx?HTTP_HOST=privacy2.msn.com&url=/anti-spam/en-us/default.aspx

AOL Bulk Sender Best Practices

http://postmaster.aol.com/Postmaster.Guidelines.php

Yahoo Best practices for senders

https://help.yahoo.com/kb/mail-for-desktop/recommended-guidelines-bulk-mail-senders-postmasters-sln3435.html

CAN-SPAM Act: A Compliance Guide for Business

http://www.business.ftc.gov/documents/bus61-can-spam-act-compliance-guide-business