Have you checked out the Adminsparadise VoIP PBX and fax server
First its FREE!
Second it automagically installs and configures your server for you.
The fax server sets up hylafax, sambafax, and avantfax -- integrated with an iaxmodem.
Winprinthylafax works with it.
There is a livecd to preview and an installation cd that automatically sets it up for you.
the avantfax package has been tweaked so instead of only uploading tiff and pdf documents you can also upload the microsoft stuff -- docs, excel etc.
there are screenshots and flash movies that walk through it.
www.adminsparadise.com/downloads.html.
Why waist your time? -- sit back, sip a margarita and let the install run.
PS it also includes a full featured phone system -- with scheduled conferencing, paging, music-on-hold etc... for free...