I posted in the other place she asked this, but I'll respond to your reponse, too, Heather! Our bunny has a litter box, which she uses unfailingly for liquid, and either in or right next to for the "pellets" bunnies drop. We use the Carefresh litter - recycled newspaper. Cat litter is terrible for bunnies - the clay is bad if they eat it, and the dust it raises is bad for them, too.

Here is the House Rabbit Society's excellent bit on what litter to use:
http://www.rabbit.org/faq/sections/litter.html#litter