Keep pets indoors in the extremely hot weather. In the shade it is still in the 100's here in the California desert. :(
Do not over exercise them or walk them on hot concrete/asphalt.
Give them a summer haircut to keep them cool.
Provide plenty of fresh/clean water at all times.
Never leave them in a parked car in the summer heat, even with the windows cracked a car is like a furnace in the summer.
Make sure sunscreen and insect repellent is safe for animals.
Other tips at ASPCA!