if you have an IMAP account then you can send the mail using the imap_mail() function of php. it is similar to mail() function but is an authorative way.. because your email account will require authorisation while sending an email
here goes an example..
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imap_mail
(PHP 3>= 3.0.14, PHP 4 , PHP 5)
imap_mail -- Send an email message
Description
bool imap_mail ( string to, string subject, string message [, string additional_headers [, string cc [, string bcc [, string rpath]]]] )
This function allows sending of emails with correct handling of Cc and Bcc receivers. Returns TRUE on success or FALSE on failure..
The parameters to, cc and bcc are all strings and are all parsed as rfc822 address lists.
The receivers specified in bcc will get the mail, but are excluded from the headers.
Use the rpath parameter to specify return path. This is useful when using PHP as a mail client for multiple users.
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