[warhorse11h]

I coined a talent called Psionics and decided arbitrarily that you could have one ability for each two IQ points. The talent cost (4).
I decided the easiest way to handle it was to cull the spell list for appropriate effects and use those as the powers available, with the same IQ requirements to learn them as they had as spells.
The ST+IQ=PST yielded the total available for their abilities.
Psionic abilities had the same ST cost as spells of the same name, but it is paid in PST. A spell that cost 1 ST would cost 1 PST as a psionic ability, reducing IQ and ST by one each. IQ loss is mental fatigue, you retain your full abilities, you just get mentally exhausted.
Example: Ranulf Redhand has ST 11, DX 12, IQ 9. His PST for his Psionics would be 20. He could power his abilities until his IQ hits 0, he would still have 3 ST, then he is dazed and unable to do anything until he has time to recover.