If you are using Vitality/Wound points Shadowforce Archer has several psionics base classes. Since they built the system from the ground up it's a better system for modern day psionics as well, not just a (bad) conversion of a system designed for D&D. It's a skill and feat psi system and when you use the skills you spend Vitality, getting exhausted just like Psi in moden/sci-fi setting usually do.
The base classes are Mentalist, Telepath and Physical Adept and like I said it fits a modern setting better than d20 Modern IMO. It was made around the modern paradigm, taking into account such changes as guns, technology, etc. Much superior to a (flawed to begin with) system designed for medieval combat.