Adobe has released a series of white papers (http://www.adobe.com/digitalimag/ps_pro_primers.html) written by a handful of the leading digital photographers, including Jeff Schewe, Bruce Fraser and Michael Reichmann. The series of 11 articles are available for download in pdf format. Topics include Digital Workflow for Raw Processing, A Color Managed Workflow, and Highlight Recovery in Adobe Camera Raw. These articles are extremely well written and the content is applicable to beginners and intermediate level photographers.

I second the motion. Just got my wife a 20D (but she's sweet enough to let me play with it, too!) and reviewed some of these documents to learn more about raw files and Adobe's new DNG format. Good, yet quick, reading at the basic level!

For those using PhotoShop, 16-bit raw files really do greatly increase your ability to salvage a shot "in post" as compared to even the largest, finest *.jpg. On the down side, only a limited number of the fundamental PhotoShop CS filters are available in 16-bit. So if you plan on doing anything cosmic with your pics, you'll end up going back to 8-bit once you're done with your histograms!

There are a lot of 16 bit plugins available for PS as well. You can also do High Dynamic Range development of your Raws, as Jeff Schewe explains, to really improve some shots.