best shampoo for dogs  

This may sound strange but all I use is the blue Dawn dish soap. It kills the fleas and is gentle on their skin. I use the blue but I have been told that the other ones work too.

try some harbal shampoo

I have a pom too. I use a dog shampoo with aloe vera in it for her skin and coat. Only bath her once a month..
As for the flea issue... there is more to getting rid of the fleas than just shampooing the dog...
They get the fleas from being outside. therefore you have to treat your yard all the way around your home (front,sides,back) and you can go to home depot and get a pest control spray for your yard (it hooks up to your water hose) it will also kill other pests but it also kills fleas.. you may have to treat your yard and then three or four days later treat it again to kill any eggs that may have hatched... this pest control stuff costs like 10.00 a bottle, but one bottle does like 12,000 square feet so 1 will probably be enough...
Then you need to spray your house... you can buy flea spray for use indoors... this will kill any fleas inside your carpeting, the pet bed etc... also, if your dog has really bad fleas, buy Flea dip for dogs.. mix it according to directions... you saturate your dogs coat and let set 10 or 15 minutes..then rinse it off.. but only dry your dog enough to keep him from dripping all over the floor..do not completely dry him...let him air dry...
To keep him free of fleas...treat your yard about every 3 months.. and go to a pet supermarket or your vets office and get the flea drops that you put in between their shoulder blades once a month... the vet or pet supermarket person can tell you the advantages of theirs versus a cheap brand like you can get from any grocery store (the cheap brands do not work..and they wash off) the more expensive brand (like 60.00 for a six month supply i believe) will not wash off with plain water after it dries and it works better..
using these step will keep your dog flea free... it works great for my pom and for the first three years of her life i lived in florida where it is much warmer and fleas are much more prominent during the warm weather...
once you get your pom and yard free of fleas, it wont be as costly to keep up with... ten dollars every three months for the yard, and the flea drops cost on average about ten dollars per month except i think they only sell them by three or six months supply... (i havent had to buy any and wont need it until next month so i can remember off hand..sorry)
with my pom, she gets a bath the first week of each month..gets her nails and paw hairs trimmed, gets her heart-worm medicine and then after she is dry from her bath we put the flea drops on her and she is fine...
I do keep a bottle of the dog dip on hand just in case we need it, but i do not care to use it often as it will dry their skin out.. oh yeah...and it stinks like bug spray too...but it works really well if your pom has alot of fleas...
I hope I was able to help..