Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
what is the minimum size ssd to run leopard on a netbook? 8GB? 16GB?

You could get it on the 8gb but you would want to do a customized install removing the printer drivers/extra languages better off with the 16gb without them to give yourself some extra space.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.