I didn't make this, but I'm posting it for all of you who can!
This is the most amazing thing I have bought for the Summer months! It is call Cold Seat and is a freezable car seat cooler. There are Velcro pockets sewn into the fabric that hold five different ice packs. You stick this in the freezer and then lay it on the car seat while you're out and about. It keeps the car seat (and buckles) cool. I only wish is had little "wings" that would cover the sides of the car seat too. When you come back home stick it in the freezer until next time you go out.
I also bought these small 8" misters at Walmart. I stick these under the Cold Seat, so when we get into the hot car we can get a cold mist of water to help cool us down.