I just fixed this problem on my bike.I completeley tore down the drive train,but after all said and done I believe i was my right side pedal. It was stiffer to rotate than the left one. Upon disassemble I found the outer bearing in excellent shape, but the inner bushing of the pedal was working it's way toward the crank;which was causing the pedal to bind. I pressed the bushing back into the proper place and relubed/re-assembled. Just like new, but if the bushing moves again it is time for new pedals.
I re-installed the bottom bracket with teflon tape and it was torqued to 350 in/lbs. The crank arms were relubed and torqued to 300 in/lbs. If you have square taper cranks the don't get lubed. Also the rear casstte was torqued to 350 in/lbs (40N/M).
Problem went away. Not sure what cured the creak, but I suspect the pedals,since that was the only problem I found.
If you can't get Bottom bracket out you might want to take it to a bike shop. If the bottom bracket is smooth and has no play in it, you might not need to mess with it. Remember to loosen the left side first(right hand thread) and the the drive side(left hand thread). Also good to soak it with a pentrating oil, to help it break lose.
Sorry, lenghty reply but hopefully it will help.