$mail->smtpsend()Sends the Mail::Internet message via SMTP to
all addresses on the To, Cc, and Bcc
lines. Finds the SMTP host by trying to connect first to
hosts specified in $ENV{SMTPHOSTS}, then to
mailhost, and then to localhost.
In a future release of Mail::Internet, smtpsend will be able to
take the hostname as a parameter, as nntppost does.