"Pose Book" is a great app I found via the Bancroft brothers that was developed by Stephen Silver. It is sadly available only on ipad, ipod touch and iphone so I can not try it out on my Android until it is available in the lion app store. I know that if Tony suggests it it is worth it. From the video on the site explaining the I am amazed at how in depth this is. If you get a chance to get it I'd love to hear your thoughts as well.
If you are not on ipods or ipads we have posted similar sites as well in these posts.