How to get IDs of child pages in 2.0.10?

Hi,

I’m trying to get the IDs of the children of the current page in WP 2.0.10. I’ve done this with 2.3 previously using something like the following database query – but I can’t seems to get it to work in 2.0.10.
Can anyone offer me some pointers on what I need to change to get it working?

$childpages = $wpdb->get_results("SELECT $wpdb->posts.* FROM $wpdb->posts WHERE post_type = 'page' AND post_parent = " . $post->ID . " ORDER BY post_title ASC");

Thanks