This is a WordPress plugin tweaked from wordpress related entries plugin, it also uses portions of the nice categories plugin to list the related posts - comma separated with 'and' before the last in the same whay that nice categories does with categories.
Example:
Welcome Marshmallow, Marshmallow theme maybe?, to theme or not to theme?, Pompey FC T610 Theme and Milk Theme for T610.
Download plugin code (ZIP file) - should be ok hopefully, but please leave any comments and Ill tweak the code if necessary.
*EDIT:* Ok, code. place< ?php nice_related_posts(); ?> where you want the list.
you can customise it thuslynice_related_posts($limit=5, $normal_separator = ', ', $penultimate_separator = ' and ', $show_pass_post =false) $limit is the amount of post to be listed (default is 5), normal_separator whatevers between the posts (default is ',' or comma), penultimate_separator is what appears between the last and penultimate post (defaults to 'and'), show_pass_post is whether or not to show passworded posts.
*For example*< ?php nice_related_posts(3, ' or ', ' and finally ', false); ?> would result in
post 1 or post 2 and finally post 2
hopefully that helps, but WP mangles code tags so sorry if theres some confusion
