Imaging USA has a video of Tom Hogarty on Lightroom.
 
From  Adobe Gives Photographers a Choice: http://iusatv.imagingusa.org/2007/01/adobe_gives_pho.html. Tom mentions that B4 was the last public Beta and that the product will ship by the end of February. He shows a little of the spot removal tool and talks about the similarities of Develop and ACR4.