Mine

GOAL (Ensure $email is structured as follows):

  1) MAILBOX NAME (min 3 characters)
    (alphanumeric|alphanumeric, underscore, period or hyphen|alphanumeric)
  2) @ Symbol
  3) DOMAIN (min 3 characters)
    (alphanumeric|alphanumeric or hyphen|alphanumeric)
  4) EXTENSION (.com|.net|.org)

if ( preg_match("/^[a-zA-Z0-9]+[a-zA-Z0-9_.-]+[a-zA-Z0-9]+@+[a-zA-Z0-9]+[a-zA-Z0-9-]+[a-zA-Z0-9]+
	\.(com|net|org)$/x", $email ) > 0 ) {
	echo "Email looks good.";
} else {
	echo "Email looks bad.";
}