Bulk email to a list of users is performed using your preferred email client. It's easy to get the list of users into most client email applications with a simple copy and paste.
1. Go to the User List as a User administrator.
2. Make sure the email address column is exposed in your list.
3. Export the list to Excel/CSV.
4. Copy and paste the email address column into your email client.
The export process above will ignore the page spanning as seen in the default user list display and export the entire list to a single file.
The above procedure works for Outlook as well as most other email clients. It will recognize the cell separators for each address automatically with a simple paste operation. It also allows you to filter the list prior to the export using the standard Project Insight filtering tools for user administration if you choose to send only to a certain group or department.