Microsoft offers some password advice and has a tool to gauge the security your password.
Other links I've found with good password advice:
• http://security.yahoo.com/choosing_password.html
• http://www.theadminzone.com/forums/showthread.php?t=10859
•
https://www.google.com/accounts/PasswordHelp
•
http://www.techsoup.org/learningcenter/internet/page6912.cfm