I stumbled upon this standard to fight Mail Fraud and Spam, its called DomainKeys or DKIM( Domain Keys Identity Management ). To my pleasant suprise, I then found out that this standard was developed by Yahoo! ( where i worked prior to CitiPals ). This standard is currently adopted by a large number of Mail Service Providers including AOL, Microsoft, Google, Earthlink, etc. For more information, see http://antispam.yahoo.com/domainkeys .
And I am now finding out, that Yahoo! Domains does not support the TXT field in domain records, which is needed to implement DomainKeys if your domain is being served by Y!Domains. For a list of Domain providers that support the TXT field, see http://www.kitterman.com/spf/txt.html ( although i should add that i don't know how accurate this list is ).