I took the MCAT on May 2. I believe that in most of my passages, the important formulas were provided. In the discrete questions however, there were formulas you either knew or didnt. I would try and remember all of the important formulas. Just practice lots of problems and they you will naturally remember them. Thermo, kinematics, mometum, Fluids and solids electricity, magnetism, capacitors, resistance are big topics with formulas I feel are tested every MCAT.
Oh and Light!!! E=hf, this is a very important equation.