This is the 2013 updated version of my IKFK Blend setup. This time I use the standard 3 joint chain structure, which is visually more familiar and easier for folks to understand. All you need are a bind, IK, and FK chain, a few blendColors nodes, and a curve to house the ikfk attribute. It's a very simple and light setup, no constraints, no SDK, no expressions, just direct connections... (13min).
Video tutorials like this and much more available in my Maya Guides, made for iBook readers (iPad/Mac).
itunes.apple.com/us/artist/jeremy-a.-parrish/id507724058?mt=11

Loading more stuff…

Hmm…it looks like things are taking a while to load. Try again?

Loading videos…