It really depends on the cat. I know Old man doesn't freak out too badly, I've tried putting water on him too see how he reacts and he just yowls sorrowfully at me. Little girl, oh my God, I can't even think about, because she would freak out so bad that she'd probably claw out my eyes! I once tried to set her down in the completely dry bathtub and she FREAKED. I almost had to throw her, she was wriggling and freaking out so badly! I've never even attempted to give her a bath. My step-mothers cats reaction to bath time was hilarious. He struggled a little bit, but he was mostly in a "what the heck is this, what the heck is my mother putting on me, what is this?!!" kind of state. Too bewildered to freak out, basically. I also had to teach my step-mother how to properly bathe a cat, haha.
Training the cat when their a kitten to get used to water and bath times is a really awesome thing to do. My friends mother used to bath the cat regularly as a kitten, so now that it's an adult, on the rare occasion it needs a bath, you can just plunk them into the bath tub and give them a good scrub down and all they do is stand there. She also add a cat the loved to swim in a filled bath tub, but those odd balls are rare.
In the case of fleas; you either need to use Brewers Yeast and put it on her scruff regularly (like about once a week) and put a small amount in her food or you need to go to the vet at get some of the "Revolution" flea medicine. It's also to prevent ear mites and heartworms, along with fleas.