Subdual/Nonlethal damage is generally healed at a rate of 1 hit point per character level per hour. If you have a healing spell cast on you, it heals an equal amount of Nonlethal as it does regular HP. And if you have Fast Healing it heals up your subdual before going to heal up your HP proper.
Aside from getting immunity to subdual damage through varying methods, are there any other ways to heal your nonlethal damage, either via feats, gear or class features?
As an side question, how does a creature with both Regeneration and Fast Healing work? Is the Fast Healing only there as a redundancy in case the Regen is trumped or do they interact in some way?