I suggest you to use "OpenERPLib" rather than "Export / Import" feature of OpenERP. OpenerpLib is nothing but a python library to communicate with an OpenERP Server using its web services.

just google it - "download openerp lib". (Sorry i can not post the link here because my karma is insufficient to publish links)

It's very easy to learn and use. Still if u stuck somewhere then let me know...

1. Create a test database with demo data, export the customer information to a CSV file, then import the CSV file again, in order to learn how the import process works. You will need to play with the system in order to understand the import process

2. You will have to do that with a SQL query. You can run a query like

select city,street,count(*) as quantity from res_partner group by city,street having quantity > 1;

the query above should list the duplicate addresses

1. The e-books are valid for older versions as well as version 7.0. Logic did not change, what changed was the web client and how addresses and contacts are stored.