Woohoo, just my department!
Ok, so originally being from Arizona (searing desert 110+ degrees) cooling off is a big thing!
First, lots and lots of available water (I had mine dripping from the spicket outside to keep it fresh and cold) also adding icecubes to said water helps a lot!
His/her color shouldn't be a big issue unless in the sun a lot - then it gets warm, but as long as he/she is short haired (or medium) it won't be as bad
The cooling bandana's "kind of" work - I say this because of the lack of humidity they don't last nearly as long as you'd like them to - the dry air sucks the moisture right out of them and then the gel gets warm. Depending on humidity levels they can be effective or not.
Lots of shade if outdoors. Mine loved our tree in the yard in AZ, I watered it all the time so it always had cool moist dirt under it.
If your dog stays indoors, the AC works wonders too :P I know mine wanted to stay in most of the summer (and now it's flip flopped with the icy death winters that I can't force them out the door) - and they would lay on my tile floor...nice and cool.
They also have the neato ice cube trays in bone shapes for summer weather
