I've done a lot of searching over the last couple of weeks. I've found
Windows software for a Hylafax server, I've found "respond" which is
supposed to work with sendfax. Because I want to use VOCP on the Linux
system, I'm pretty much "stuck" with using sendfax. However, I haven't
found much about "respond" so I'm not quite sure how it's supposed to
work.

What I want is the equivalent of printer drivers for Windows, where,
from any application, you could print the document, it would ask for the
phone number and a cover page, and send everything to sendfax on the
Linux box. Does anyone know of any such software?

Thanks!