I've seen some good coats too, I'm pretty sure you freeze them, and they keep the dog nice and cool, I saw them at a show a lady there made them, kinda like the crate mats that you freeze, same idea.

In addition to the great advice already given re times of day to avoid exercising etc, you might like to consider Wet coats or similar.
I use double layer fleece type coats for my lad who does`nt do well in hot weather. Being double layer, when soaked through its the layer touching the dog stays damp and cool as the fabric weave keeps it from evaporting through the tope layer.
In UK it does`nt get as hot as where you are of course so would need topping up more often than here but on a very hot UK day my lads coat keeps him comfortable for about three hours per soaking when out and about. [ I check frequently of course for when it needs re-soaking ].

**Should not be left on a dog which will be unattended for long periods in case it needs topping up sooner than expected.

There are also excellent lightweight reflective coats specifically made for helping dogs keep cool when outside and even purpose made breathable boots to protect paws on hot surfaces.

Some links you may find useful to show what sort of products are available :

Cooling Tablets [ check suitability first ]

http://www.lamp-post.co.uk/proddetail.php?prod=CH1291

Boots [ can`t get it to link directly so when page comes up just click on the left on the Summer boots index marker under Style ]:

http://phoenix.about.com/gi/dynamic/...e%2Fboots.html

Wet coats [ there are many types manufactured along this line ] :

http://www.mydeboxers.com/CPcoats.html

Cool Mats

http://www.drsfostersmith.com/produc...CID=C12188x007

Crystal Body wrap

http://www.drsfostersmith.com/produc...tid=9441&rel=1

Crystal Cooling bandana [ bottom of the page ]

http://www.doghaus.co.uk/coats.htm

Cooling Jacket [ Highly recommend this one ]

http://www.agilitywarehouse.com/prod...il.cfm?id=1941

Heat reflective coat

http://www.agilitywarehouse.com/prod...il.cfm?id=1650

Hope something there is helpful for your lad :smt001

We live in the far north of Scotland so we don't have a problem with the heat but