Saving checkboxes in custom post type

Hi

I’m working extensively with custom post types. Although I can get it to save any single value – I am having issues figuring out how to save multiple answers – ie checkboxes.

This is roughly the code I use:

I declare the checkboxes like this:

"languages" => array(
"name" => "languages",
"title" => "Languages",
"description" => "",
"style" => "checkboxes",
"options" => array(
"1" => "option1",
"2" => "option2",
"3" => "option3",
"4" => "option4")
),

I display it like so:

elseif(($meta_box['style'] == 'checkboxes') && (!empty($meta_box['options']))) {
echo '<td>';
foreach($meta_box['options'] as $radio_value) {
echo '<input type="checkbox" name="'.$meta_box['name'].'_value'.'" value="'.$radio_value.'"';
if ($meta_box_value == $radio_value) { echo ' checked="yes"'; }
echo '/> '.$radio_value. '<br/>';
}
echo '</td>';
}

and my save function – which works for eveything except obviously checkboxes:

if(get_post_meta($post_id, $meta_box['name'].'_value') == "")
add_post_meta($post_id, $meta_box['name'].'_value', $data, true);

elseif($data != get_post_meta($post_id, $meta_box['name'].'_value', true))
update_post_meta($post_id, $meta_box['name'].'_value', $data);

elseif($data == "")
delete_post_meta($post_id, $meta_box['name'].'_value', get_post_meta($post_id, $meta_box['name'].'_value', true));
}

How can I adjust this to save checkboxes – of course the question would also be whether it would require a db row for each option or a single row and if so, I would probably need to explode it first.

any ideas would be greatly appreciated.

Thanks in advance