Example of using the Import Users From CSV filters to change column names and data before import.

my_is_iu_import_userdata.php

<?php
/*
Plugin Name: PMPro Custom Import
Plugin URI: http://www.paidmembershipspro.com/wp/pmpro-customizations/
Description: Custom Import Code for PMPro
Version: .1
Author: Stranger Studios
Author URI: http://www.strangerstudios.com
*/

/*
	Change some of the user data columns.
*/
function my_is_iu_import_userdata($userdata, $usermeta)
{
	//password => user_pass
	$userdata['user_pass'] = $usermeta['password'];
	unset($usermeta['password']);
	
	//billing_email => user_email, user_login
	$userdata['user_email'] = $usermeta['billing_email'];
	$userdata['user_login'] = $usermeta['username'];
	
	//join_datetime => user_registered
	$userdata['user_registered'] = $usermeta['join_datetime'];		
			
	return $userdata;
}
add_filter('is_iu_import_userdata', 'my_is_iu_import_userdata', 10, 2);

/*
	Change some of the user meta columns.
*/
function my_is_iu_import_usermeta($usermeta, $userdata)
{
	//rename some fields for PMPro
	$usermeta['pmpro_baddress1'] = $usermeta['billing_address1'];
	$usermeta['pmpro_baddress2'] = $usermeta['billing_address2'];
	$usermeta['pmpro_bcity'] = $usermeta['billing_city'];
	$usermeta['pmpro_bstate'] = $usermeta['billing_state'];
	$usermeta['pmpro_bzip'] = $usermeta['billing_zip'];
	$usermeta['pmpro_bcountry'] = $usermeta['billing_country'];
	$usermeta['pmpro_bphone'] = $usermeta['phone'];	
	
	return $usermeta;
}
add_filter('is_iu_import_usermeta', 'my_is_iu_import_usermeta', 10, 2);