Anyone know anything about "OBD II"?

[avos at cochlear.com.au]

     I know a few things about OBD II, but am after more information. I 
     know that it is an attempt to standardise diagnostic equipment for 
     ECUs. I think that the method of doing this is to have a standard 
     communications protocol that can be used to communicate with any OBD 
     II compliant ECU. If anyone can point me in the direction of where I 
     can find information about OBD II it would be appreciated. I am 
     particularly after the communications protocol, as I would like to 
     write some software that allows me to read parameters from the ECU 
     like sensor values and I would also like to be able to read the 
     standard ECU maps.
     
     Any information would be appreciated, especially WWW sites that have 
     information.
     
     Thanks in advance,
     
     Adrian Vos
     avos at cochlear.com.au