I’ve been a little lax with this. I actually saw the post as soon as it was posted, but was too busy to link it.
Podcast #45 is a video tutorial. In it George shows us Catalog use in detail. He takes us through from Import, showing us what Lightroom takes from the photo to how Lightroom deals with our photo in a catalog. Get the video from George’s blog, or from iTunes. The rss feed is http://rss.adobe.com/www/special/light_room.rss
I’m sure the observant among you will notice the 1.3 ID Plate and the different looking Export dialog.