There's an interesting article up here with Steve Furber, one of the designers of the BBC Micro and ARM processor. It's been linked to from Slashdot, which is where we came across it.
 
There's some background in there on the development of the original ARM designs, as well as the StrongARM and the current SpiNNaker project, an attempt to come up with a more biologically based style of computation.
 
All fascinating stuff, and especially so at the moment with the explosion of ARM-based computers out there.