The above links go to the Grocery, Natural + Organic, and Gourmet Foods departments at Amazon. These mostly sell non-perishable items, but do include some frozen foods.

http://fresh.amazon.com/

Amazon Fresh is a pilot program, currently in the Seattle area only. It features just about everything you can get at a grocery store, plus a partial selection of items from regular Amazon departments (books, music, electronics, etc.). A lot of companies went bankrupt trying to do this; Amazon seems to be taking baby steps to make sure it can be profitable.