This plugin was perfectly fit for what i needed to help a client. I just made some minor tweaks to it, adding localization tags where needed and a textdomain to make it perfectly translatable - and adding a few other fields to the example.csv file.
You can find my fix along with pt_BR .po and .mo files here: http://moraleida.me/plugins/import-users-from-csv.rar
Feel free to scan it for errors and incorporate to your main plugin if you want to.
Thanks heaps for developing this!