DDR400 means entire DDR400 line?

If a mobo says it supports Dual Channel DDR400, does that mean that I can get DDR466 because its in the 400 range?

I'm pretty sure the answer to that would be "no". But if someone can prove me wrong, ill give u a cookie.

supporting ddr400 means the motherboard will run at 200mhz.

The motherboard will run the ram at whatever you tell it to, not the other way around - Meaning as long as its DDR, it'll work.

It will work, but it will run at 200mhz. Unless of course you are overclocking, which is why we are all here. Some motherboards will let you run your ram faster than your FSB, but that is useful only for testing, as you will not get any more performance out of it.