Hi

Love the box and I think I know what you're trying to achieve with the pics, however I think you are over-complicating matters by trying to go that route. I think you may be better having a look at various stepper-drive IC datasheets eg: http://www.robotstorehk.com/5804.pdf these or others may provide the functionality you require already built-in.

As for your progression to Pics your 3 main choices of language would be basic, assembler and 'C'.

Regards

Dave