I found a really great flea/mosquito repellent and flea killer: cedar oil. I've resorted to using the topical spot treatment last summer because the fleas were so bad. This summer, I initially started using diatomaceous earth as a topical flea powder (I use food grade DE by earthworkshealth.com) but by July, I was having to use it every day rather than every week or so. I found this site: http://www.cedaroilstore.com/DR_BEN_S_PAWS_CLAWS_16_OZ_SPRAY_p/ap5001.htm
I bought a 32 oz bottle to try. It kills the fleas on the dog and will repel them as well for the next several days. Caution: You'll want to spray (use the mist setting for short coated dogs) your dog outside, the cedar odor is a bit overpowering if you do it inside. My dog stopped biting and scratching immediately after spraying and remained that way for a few days and I just sprayed her again. This was a whole lot easier and quicker than using the DE -- she's a big dog. For my cats, I mixed a bit of chrysanthemum powder in the DE and sprinkled it on my cats when they started biting and scratching themselves and it worked like a charm.
But, you CAN make your own, from dried chrysanthemum flowers. I use the DE/mum powder as needed (when the critters start scratching). The cedar oil and DE/mum powder is non toxic and a whole lot cheaper and way more effective than the spot treatment stuff.
For the yard, you and spray it with cedar oil or google for beneficial nematodes for fleas. There are two kinds that will take care of the flea eggs and the adult fleas that are in your yard. You have to apply them twice a year to be effective. This is where I've ordered them. It seems to be the cheapest place: http://www.arbico-organics.com/.
I've done the nematodes in the past and it does help keep the population down. I didn't do it this year, I don't know if the nematodes I put down last year were still around or not, sometimes they will sometimes they die out. I think next summer, I'm going to try the cedar oil.