It’s important to remember that email is not an unregulated industry in the US or abroad. Research the various legal requirements that may apply your mailings. The US, European and Australian email laws listed below are a good place to start.

US Laws:
CAN-SPAM - http://www.ftc.gov/bcp/edu/pubs/business/ecommerce/bus61.shtm

European Laws:
EU Directive on Privacy and Email : http://www.spamlaws.com/f/docs/2002-58-ec.pdf
Each EU member country has their own law related to the Directive. Visit the
following site for more information: http://www.euro.cauce.org/en/countries/index.html

Australian Law:
http://www.dbcde.gov.au/online_safety_and_security/spam