Summer is in full swing here and this is exactly how I feel when I'm running.
To help you beat the heat, here's a few of the things I (try) to do.
1) Drink plenty of fluids. Try to add some electrolytes. I prefer nuun over any of the other popular sports drinks.
2) Run earlier in the day or later after the sun has gone down. I tend to run early in the morning because the rooster wakes me up early =)
3) Wear light colored clothes and light weight fabrics.
4) Pick routes that are shaded. My tree tunnel is perfect for this, although it gets boring going back and forth, back and forth...
5) Carry water with you or stash it on your route. Freeze part of it and top it off when you head out to keep it colder longer.
6) Run by effort and not pace. This is the hardest for me to do. It's so hard to see my pace/ mile slow down as it heats up.
But, I suppose I can't complain too much about the heat. There's crazy runners out there who purposely train to run the Badwater Ultra Marathon. You know, in Death Valley, where temperatures can reach 130* F? Yeah, I'm not that crazy...