I use normal human nail clippers. And I find that they work just fine. I've always used them for my cats as well.
Some use baby human nail clippers. Only difference is that they're much smaller.
I find that the small animal "clippers" aren't all that great. I can't SEE enough of the nail. With the human clippers, I just rest his nail ontop of the bottom blade, I can SEE how far his nail is, and see where the quick is, and then clip off the tip.