How can I add login and registration page for members with civiCRM?
So you want a registration page for your site where they input their username, email, password, and city? If I'm understanding you correctly, do it like this:

I haven't used the Wordpress version, but it seems like it should be similar to the Drupal one - I create a profile in CiviCRM: http://www.yourdomain.com/civicrm/admin/uf/group?reset=1

In the settings for it, I choose it to be used for user registration and view/edit account. Username, email, and password you don't have to add to the profile because those are the minimum required elements for a user account.

Then any field you add there will be added to the registration page as well as their user account page (so they can view and update the information).



UPDATE: Forgot one step - you will need to enable an option in WordPress for the option to show up under profiles: Turn on "anyone can register" under Settings > General.