A friend of mine told me that PrCs from MoF are not compatable with 3.5. He raised this concern specifically in regards to the Spelldancer PrC. I was under the impression that MoF, even though it was printed for 3.0, was usable in 3.5.
The question this brought up is more broad though. Does it say somewhere if 3.0 FR material can be used in 3.5, or is all of it useless now?
Edit: Actually I was just looking at PGtF and it does seem to address this issue. It says that if a PrC from MoF was not updated then it can be used as it was printed in MoF. I guess I need to show my friend this. Thanks for pointing me to the PGtF, I didn't know where the issue was addressed.