How can I make posole "pop" faster? I have run into this a few times.   I soak dry posole overnight, and then add it to my sweated/sauteed vegetables, add water, and stir it regularly, and it still takes over 4 hours for the kernels to pop.   Is there a part of the process I am missing or doing wrong, or could I just be dealing with old posole?

Posole is essentially Nixtamalized Corn, or hominy.
Use a pressure cooker.
Try for example this recipe: 

http://ljcny.wordpress.com/2011/09/13/chicken-pozole/

where dried hominy is cooked in a pressure cooker.