Ad Astra Observatory

http://www.tigoe.net/pcomp/code/archives/picbasic_pro/000245.shtml
http://www.sparkfun.com/commerce/product_info.php?products_id=8368
http://arduino.cc/
http://jeff.medkeff.com/robotics/hardware/focuser.html

not strictly stepper:

http://www.makezine.com/blog/archive/diy_projects/62.html and
http://www.instructables.com/id/EVIV78PF1B3RH1U/