This link will take you to a map that shows where the users of Orkut live, based on their zip codes. My understanding is that this is not an Orkut sanctioned activity. The value in this can be the visualization of RFL volunteers using Seibel as a database for the same type of information. On the same note if this is not sanctioned by Orkut it is scary to see who has access to the database.
At the bottom of the mpa eter your zip code in the first box and leave the second box blank. Then go to the top right corner and see the useres in your area.