Use a face towel to wipe them down. You don't need to lather them up, just gently wipe them down and rinse. Always wipe their face with the wet towel, never pour water over their head. Watch them like a hawk, it is hard for them to stay on their feet in water. They are also very curious and will dip their face in the water if you are not careful.
Finally, you want to always keep them warm. I use 2 towels. The first gets soaked quickly, so then you can move them to the second towel. Never let the kitten go until they are completely dry. I use a hair dryer on low heat and low speed. Keep the dryer in constant movement so it never sits on any one part of their body to avoid burns. And voila! You have a wonderful and fresh smelling kitten!