I changed by editing wp-register.php. Try to find these lines:
for ($i = 0; $i < strlen($pass1); $i = $i + 1) {
$stars .= '*';
}
$message = __('Login') . ": $user_loginrn";
$message .= __('Password') . ": $passwordrn";
$message .= get_settings('siteurl') . '/wp-login.php';
wp_mail($user_email, sprintf(__("[%s] Your login
information"), get_settings('blogname')), $message);
Now you can edit that into something like this:
for ($i = 0; $i < strlen($pass1); $i = $i + 1) {
$stars .= '*';
}
$from = 'From: '.$_POST['weblog_title'].' <info@***.**>';
$message_headers = "$from";
$message = "Your registration has been successfully set up.
You can log in with the following information:
";
$message .= __('Login') . ": $user_loginrn";
$message .= __('Password') . ": $passwordrn";
$message .= "Don't forget to change your password after you
login. You will be able to do this in your profile.
The Blog Team
";
$message .= get_settings('siteurl') . '';
wp_mail($user_email, sprintf(__("[%s] Your login
information"), get_settings('blogname')), $message,
$message_headers);