I've gone back to Leopard, it doesn't seem to be heating up so much, but I haven't really tested. I'll give it a few more days. I asked about the temps because I thought this machine would be cooler than my MBP, but it isn't. I really love the macbook air, it's the perfect machine for me (asside from a barely noticeable monitor issue and the heat).
I found safari 4 caused me more heat issues than 3 .....
So I use safari 3 still on my MBA