I had some trouble with litter box digging with my little fuzzy for the
first few weeks I had him.  He would stick his head down into the litter
and run around like a pig rooting through the mud, sending litter spraying
everywhere.
 
I solved this by buying a deeper litter pan.  The one I got was actually
Rubbermaid 8 qt Dishpan, available at Caldor or KMart, for about $6.  It's
a little much for a litter pan, but it's worth not having to clean up all
the time.
 
Depending on how big your ferret is, you might need to cut down one side
to make it more accessible, especially when he isn't totally litter
trained yet.
 
Good luck
[Posted in FML issue 1451]