With all the information on the web about the upcoming London Olympics, I'm surprised that I cannot find anything that explains what the ticket codes mean? I'm applying for seats now, and I cannot see anywhere what A means, or B or C or D or more important of all, AA? Obviously the higher the price the better the ticket, but what does it really mean?

One thing I'm particularly wondering about are the basketball finals. What is the difference between AA and A?

Anyone know? Anyone better than me at searching?