IN the config for cgminer you can set ranges for the fan, the gpu-memclock, etc. Thats what I do and it seems to handle it fine. My 290x overheated and shut itself off once... which made me go that route.
I just installed Teamview so I can keep an eye on my Miners from work. Slow, and I'm wondering how it will handle it when one of the 280x's freaks out locks the machine.