I won't go into great detail, but basically, Adams was about getting the sharpest possible images of landscapes, and then expanding the tonal range of the photo to get stunning results.
I wanted to try an Ansel Adams-style B&W today. Here's how it turned out.
click to enlarge, or see it on Flickr
Shutter Speed: (5 exposures)
The way around the relatively low (compared to an eye) dynamic range of a digital camera is similar to HDR. So similar, in fact, that I use the same program as I do for HDR: Photomatix. Apparently, snow should be exposed at Zone 7 if possible, which basically means it should be very white, and close to losing detail, but not washed out. So to expose this image, I used "spot" metering on my camera, and pointed it at the brightest spot in the image. It's pretty close to the center; right where the snow is purest. Your camera's meter wants you to expose everything at Zone 5, which is a "proper" exposure. Every stop on your camera is a Zone, so to get Zone 7 snow, I bumped it up two stops from what the meter told me to. From there, I took another photo at every stop going down until my histogram had no more white pixels. For this photo, that was 5 exposures.
In post-processing, I put the 5 images into Photomatix, and told it to "average." This gave me a nicer-looking image, but more importantly, expanded the number of tones I had to work with. From there, I applied a Channel Mixer Mask layer to desaturate the image, and bumped up the contrast quite a bit (which I could now do without worrying about posterization). Now I had my Zone 7 snow, but the trees were in Zone 2 or 3—dark, but with some detail. This is better than just getting an "average" exposure where my snow is probably at Zone 6, and my trees and rocks are at Zone 4 or 5.
Finally, I applied an Unsharp Mask to really make the details pop, just like Ansel Adams liked it. I know you're not supposed to do this until you're ready to print, because it's a destructive editing technique, but I have no plans to print this. It's kind of a poor photograph—not a very good vantage point, and nothing interesting in the foreground. I just wanted to test out the Ansel Adams approach to landscape photography.
Link me any images you try with this technique in the comments.