Use a magic eraser; it'll tear the eraser to shreds but the keyboard looks like new!
I use a lightly damp paper towel regularly with no ill effects.
My keyboard is, unfortunately, used by other people and it is disgusting. Anyone have any advice on how I can clean it without damaging it?
Another benefit with having young kids, is that you always have baby wipes around. They are perfect for cleaning keyboards... damp and anti-bacterial.