My understanding (based on the little technical info provided during the .NET Launch party in Las Vegas last month) is that unmanaged code allows you direct contact with the hardware as opposed to the CLR handling that low level happiness. The implication being that you are responsible for your own memory mangagment, garbage collection, etc. (primarily an issue for C and C++ folks!)

Does this sound like it lines up with your understanding, or am I totally off-base ;).

-Brett