One Page Rules has updated their rules set for 40k with a look at the Psykers.
From them to you:
today we are updating our 40k and Kill Team systems to a new version which completely re-designs how psykers and psychic abilities work. We decided to expand on the psychic portion of the game, allowing you to upgrade your mastery and pick whichever powers you want. In addition to that we added advanced rules for denying the witch and perils of the warp, just to give psychic combat a little more spice.
There is more to come soon, so keep your eyes peeled, enjoy!