It's an easy mod, although with a fair amount of small edits to about a half dozen forum files. Of course to truly integrate it, it also requires edits to Feeds, Sitemap, Your_Account, blocks, and anywhere with links to forums and topics.
You basically have to edit the links to forums and topics to include the title in the URL, and the title has to be run thru a simple function first, to remove unwanted/invalid characters.
From there it's just a few extra taps for the new URL's.
An example before and after might look like so, where
$forum_data[$j]['forum_name']
is the title of the forum
BEFORE
'U_VIEWFORUM' => append_sid("viewforum.$phpEx?" . POST_FORUM_URL . "=$forum_id"))
AFTER
'U_VIEWFORUM' => append_sid("viewforum.$phpEx?" . POST_FORUM_URL . "=$forum_id&title=".gt_url($forum_data[$j]['forum_name'])))