controlling multiple stepper motors 20+

Im trying to find out how to contol lots (20+) of stepper motors at once...programmed through a PC
some moving together, some moving on their own.
Its for kinetic art project forgive me.

A little more detail is required to suggest much outside of random guesses.

If you are using XP or later, you need inpout32.DLL to use LPT1 parallel port. You will need driver boards for all the steppers that only require step and direction input. You will need a few demultiplexer chips to spread out the 8 bit data byte to address each motor or group. You also have 4 or 5 bits in the control byte to use, maybe for step pulses.
Have fun

I forgot this is in the Microcontrollers section. You can use Microcontrollers and MOSFETs instead of driver boards. That way the Microcontrollers can keep running the motors and just access them with the PC to change speed and direction.