Cycle several towels in your dryer. Run warm water in your bathroom sink (be sure the room is warm as you can stand) Put several DROPS of Dawn dishwashing lotion into the water (after the water is turned off) swish it around with your hands. Bring the kittens into the bathroom (use two tall containers- baskets, boxes, something to keep them contained in a small area (to keep them as warm as possible) dunk the kitten''s rump into the water, have a washcloth handy as the fleas will beat feet to the head. Carefully wipe the top of the head and face and chest with the damp wash cloth, be sure and rinse with warm (not hot water) towel dry with a regular towel. Wrap the kitten up in one of the towels that you cycled in the dryer and pass the kitten off to someone in the house who can hold it close to their heart and cuddle it until it is completely dry. Once dry comb the kitten with a flea comb (a baby comb works too but a flea comb is better) The bath will stun the fleas not kill them- but not bathing the kittens and getting rid of the fleas means the kitten could die from anemia. Just be sure not to get any soap in their eyes or the inside of their ears and be sure that you have them completely dry before returning them to mom. She is going to hiss at them. If she rejects them, then you have to bath her in the same fashion so she smells like the babies, besides if they have fleas, so does she. If no one is available as a kitty sitter-dryer- then do one kitten at a time until all have been deflead and bathed.
Any stray fleas pluck off with a pair of tweezers and snap them with the tweezers to kill them. Drop the fleas in a jar of hot hot hot water.