They don't need much.
Our daughter told us she was bringing home 2 ADFs because they were part of their science curiculum and it was the end of the school year. We went out and bought a 10G starter kit (came with the filter, light and food). For 3 months all we had were frogs. They NEED places to hide--they are very shy. We bought a lava rock with a hole in it and some plastic fake plants. They seem to be happy. I know at our LFS they tend to hide under the decorations.
For food I do a mixture of bloodworms (frozen! the dried ones are worthless in my opinion) and regular fish flakes. I think they are wonderful! If you do decide to add fish to the frogs, choose carefully and make sure they are community fish. Unfortunately, they make nice treats for other aggressive fish.
This website shares some basics about ADFs:
http://allaboutfrogs.org/info/mypets/dwarfs.html
GOOD LUCK!
-M