PHP email validation

function checkEmail($email)
{
$pattern = “^[_a-z0-9-]+(\.[_a-z0-9-]+)*@[a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,3})$”;
if (eregi($pattern, $email))
{
return true;
}
else
{
return false;
}
}