Good articles describing the infastructure of large commercial sites like Amazon.com?
This may be useful to you..
http://highscalability.com/amazon-architecture
Besides this website contains architectural information about other high volume websites.
Also have a look at this videoThe Amazon.com Technology Platform: Building Blocks for Innovation.
The guys at software engineering radio have done an interview podcast with Werner Vogels, who is the CTO of amazon.com.
Quite interresting and a lot of detail.
Take a look at these two also: