Documentation on Binary Protocol?

[Bryan Duxbury]

Has anyone written up a spec on the binary protocol? I'm sure it  
could be deduced by reading the code, but it would be something nice  
to have on the wiki. It would also serve as a good starter for  
discussion around alternative protocols. If it doesn't exist, I'd be  
glad to start writing some stuff down, but don't want to duplicated  
effort.

-Bryan