What's the differance between Religious and Spiritual Satanism?

These terms do not have any set definition as far as I've seen. I have seen different groups use these terms interchangeably, and no one seems to agree on their definition. I have seen Theistic Satanists use both the terms "Spiritual Satanist" or "Religious Satanist" to differentiate themselves from the Philosophical Satanists such as the LaVeyan's. However, I have also seen the term spiritual Satanist used instead of philosophical Satanist, since the term spiritual does not specifically imply a belief in any deity. Yet other philosophical Satanists still consider themselves religious, since religion is simply a set of beliefs, and does not have to include deity worship. So, I would say that all of these terms are rather fluid - the only one I've seen being used consistently is philosophical Satanism (to refer to the atheistic varieties), and that to avoid confusion you might simply want to ask for clarification from any Satanist using one of these terms to define themselves.