Yes, I do -- and I like 'em a lot. Although, not for everything. I love railscasts.com because of their concise and properly paced screencasts. Peepcode's, not so much. They try to cover way too much in a very short span. With that being said, I don't see them as a replacement for documention (for obvious reasons), but sometimes a 5-10 minute screencast showing a feature can be easier & funner than spending 30 minutes bouncing around documentation.