Good choice, both in frame and in doing it yourself. I've done this a few times and it's worth the effort. You will need a few special tools, but most can be done with "regular" tools. It's pretty easy as long as you read the directions for each component that you get. A few tools that are handy: assorted sizes of cheap spanner wrenches, a chain whip, a cassette socket (get the one that works for both cassettes and bottom brackets), and metric allens. I am building a new Yeti ASR right now, I am going pretty much XTR along with a few things I already had. I like ISIS drive BB's/cranks, and I did already have a good set. I ordered my frame a couple weeks ago, and wouldn't ya know it, I work 12 hour days this week and it arrived last night. Bummer. I did get to work on it for about an hour last night and this is about as far as I got:
http://www.geocities.com/mdwsr/yeti.html