Well, you didn't specify which Intel dual core...the core 2 duos? the pentiums?? If you're referring to the pentiums...(prescott to be exact rofl), yes, it will run hotter than the AMD. But the core 2 duo's run cooler than the x2s, that is unless you overclock them but still even if you do overclock them with a good cooler they still run cooler than some x2 chips.
Like others have said, it's totally dependent on what model you're using, and the situation it's being used in. You can't compare an X6800 overclocked to 3.2ghz running on Water Cooling and an X2 running Cool and Quiet on air.
If the situations were EXACTLY the same, I'd say that AMD run cooler, just from personal experience.
I run an X2 3800 OC'd to 2.6ghz per core running on Air Cooling and I've never seen it go above 50 under load.