Link Harvest will go through all of your posts and pages and compile a list of all external links. Then it will create a live updating linkroll for yo
You can re-harvest your links at any time by clicking the (Re)Harvest All Links button on the Link Harvest options page (Options > Link Harvest).
Yes, simply go to the Link Harvest options page and use the links under the 'Backfill Empty Titles' heading.
That about does it - enjoy!