You can import a list of profiles using the 'import people' tab. This will allow you to import an CSV of profiles you'd like to add or update to your SiteWrench site. You can export a CSV of existing members and modify that CSV and import that modified CSV.
When adding new profiles via the import, you can include a column called Password. Any value entered into this column will be used fo the password for new profiles. This will not update the password for exsting profiles.