How do I get rid of fleas on 5 week old kittens?

Hi,q

I'm new to this site and in need of some help. I've rescued two litters of kittens, an older single kitten and two adult cats from a kill shelter (they were about to be put down in 24 hours).
The youngest ones are about 5 weeks old and have a pretty bad flea infestation. I had another litter with fleas a couple of months ago and with them I was told to just wash them with Dawn and keep combing the fleas out. I don't know if any of this helped but it surely didn't remove the fleas. The fleas only went away once I used Frontline on them when they were old enough.
But these new kittens are a lot worse than the others were so I really want to use something on them that will actually kill the fleas. Does anyone have any suggestions for something I can use on them and where I can get it? I've heard of some sprays that can be used but I don't know the name of it. My vet doesn't have anything.

I was also wondering if someone could suggest a good dewormer that I can use on adult cats and kittens? I'm hoping go find something inexpensive that I don't have to go to the vet for.

Thanks a lot in advance,
Rocktosh

http://www.catsofaustralia.com/kitten_fleas.htm

It mentions Dawn as well, but goes into some detail, specifically submerging the kitten up to their neck so the fleas get drowned and are isolated on the head.

Also, I've used flea combs on tiny kittens, one has to be persistent, but then again, we aren't talking as much surface area as an adult!

Bless you for rescuing. If you have sympathetic friends, maybe they could chip and help?