Simply BitFax Professional Edition

You can create multiple individual password-protected fax mailboxes, even with only one phone line. Attach a cover letter and fax a laser-quality document directly from popular applications such as Word and Excel without having to print. The pager notification system alerts you to fax messages on your pager or pager-enabled phone. You can also automatically forward faxes to a remote location when traveling. Connect, manage, and use more than one modem in the same system: with more than one phone line and modem, you can simultaneously send and receive multiple faxes.