Network.Mail.Client.Gmail でのメール送信方法 ref: http://qiita.com/satosystems/items/c6c57d6d3b813d3dcb23

Gmail.hs

{-# LANGUAGE OverloadedStrings #-}

import Network.Mail.Client.Gmail
import Network.Mail.Mime

main :: IO ()
main = sendGmail
    "foo@gmail.com"                           -- username
    "password"                                -- password
    (Address Nothing "from@example.com")      -- from
    [Address Nothing "to@example.com"]        -- to
    []                                        -- cc
    []                                        -- bcc
    "Subject"                                 -- subject
    "body1\nbody2\nbody3\n"                   -- body
    []                                        -- attachments
    30000000                                  -- timeout (in microseconds)