I have some models that use IKs in their animation. Will these work in Unity free if I import them or do I need to upgrade to Pro? I can’t tell if the listing under Mecanim means that Free doesn’t support IK at all or if it’s only if you use Mecanim that IKs aren’t supported.
Also can anyone suggest a good tutorial for importing models and animation using the Legacy system?
Unity doesn’t import IK animations. You just bake them into bone’s animations. For both free and Pro.
Unity’s IK are not what you think they are. It is not the same of your Maya/Max/Blender IK system.
Ah. Does that mean I cannot modify the animations after they are imported? That the animations are “fixed” in place? (Not sure how better to describe that).
And thumbs up for Buckethead. 
If the Iks animations are not working try, go back to maya and use Key> IK/FK Keys >Set IK/FK Key.
then export as FBX with baked animation, skns, blend shapes, constrains, skeleton defenitions and open that file in Unty, set the anmation and it should work 
It took me about two weeks to learn of this