Is it possible to set up a joint controlled morph based on two joints? What I am thinking of is when you bend the foot and the toe bends in the oppsite angle when you're using IK. I'd like to be able to control how the shoe bends when doing that kind of motion. 

Most of the stuff I've seen on JCM has to do with one joint. Does anyone know of any information on this?

Yes it's possible. How well it will work with IK on is the question. I've never thought to try it myself to be honest. IK in Poser is a bit wacky to begin with, so who knows. But making the toes bend when the foot bends is definitely no problem on its own. 

~Shane

Regardless of IK you could setup Dependent Parameters of the Foot that affects the Toe...this should work. DP's is a very powerful little tool!

 Here's a tutorial on dependant parameters that finally helped me get my head around the concept...

http://poserfreestuff.zenryokuhp.com/detail/aglwb3Nlcml0ZW1yEgsSCUZyZWVTdHVmZhjUt70DDA.html?ln=en

The author is presently writing the next tut in the series and will post it upon completion.  This is the kind of stuff that should really be in the official manual.