remove results from search results based on custom meta value

A quick test on my local copy shows nothing with a custom parameter (as expected) – do all posts have that parameter?

Sorry, save yourself from clicking, but what I ended up using based off the google group posting:

// query for a given term ("search_term") in some given categories (7 and 8)
$search_query = new WP_Query();
$search_posts = $search_query->query('s=search_term&cat=7,8');
// build loop
foreach($search_posts as $search_post) {
        setup_postdata($search_post);
        // do stuff
}