How to sort the admin area of a WordPress custom post type by a custom field

When editing one of my custom post types I want to be able to list all entries by a custom field instead of the date they are published (which, for a custom post type probably isn’t relevant). I got a lead from the comments of a blog post about custom post types and the author said it was possible and that he even made it so you could click on the column names for a custom sort. He mentioned the posts_orderby function which I noted in my own comments but now I can find the blog post anymore. Any suggestions? I saw one solution that used