I'm a little late to this thread, but let me say a word about our Lightroom Help (since I wrote it). The in-product Help is indeed scant--it's just one chapter of the entire online help content, which is here:
http://help.adobe.com/en_US/Lightroom/2.'/index.html. We put most of it online because it provides us many benefits, including the capability to update it quickly.
In fact, we have an entirely new online help system now, called Community Help. In addition to our own documentation, we have a custom Google search engine that includes the best learning content from around the web. So if you go to the link above, you can search not just Adobe content, but all of the instructional content we've included in our index. In addition, there's live commenting on the help pages, with expert moderators (including some folks from this forum). So you can ask questions, get answers, share insights, point others to good content, and easily find text and video tutorials.
If you go to the Lightroom Help and Support page,
http://www.adobe.com/support/photoshoplightroom/ (which is where you land when you choose Help > Lightroom Help from within the product), you'll also find links to a bunch of video tutorials hosted by AdobeTV.
Please, check it out, and enjoy.