I changed $term->slug to $term->term_id on line 104 to get the term links working properly.
Other than that, the plugin does what it's supposed to, thanks!
(My post types don't support 'author', so I also had to change line 68 to 'title' so that the taxonomy columns weren't the first ones. That's due to my setup, though, not the plugin. Everything was nicely commented, so it was easy to figure out the required change. Maybe for future releases, have it check to make sure 'author' is supported & provide a fallback if not, or provide a settings page that allows us to pick which column to place the new ones after.)
http://wordpress.org/extend/plugins/custom-taxonomy-columns/
