bicycle pedal design specifications for threads
Just about all pedals for bicycles will use the same threads. According to Sheldon brown the standard size is 9/16" x 20 tpi threads. One piece "American" cranks use 1/2" x 20 tpi threads, but these are only found on low end bikes and children's bikes.  There's been a couple other sizes used in the past, but almost all modern bicycles will use the two above sizes.

It's also worth noting that the left hand pedal uses a reverse (counter-clockwise) thread to prevent it from loosening on it's own when pedaling.  The right hand pedal uses a standard (clockwise) thread.