For about a year I’ve been using a free fax service (http://voicemail.k7.net/signup/). People can also call my fax number and leave a voicemail, so you could use it as a voicemail number. When you sign up for the free service, you get an assigned phone number. Mine is a Seattle number. I believe you can pay extra for a local number.
The faxes come in as TIFF files that open fine in Microsoft Image Viewer. I didn’t need to set that up. When I clicked on the attachments they just opened. Some free services require you to use their software.
Note: I used to have another number, and I lost it. The reason is I don’t get very many faxes. If you let your account stay inactive for too long, you’ll get your number taken away. To make sure this didn’t happen I signed up for a weekly fax advertisement to come to my free fax number. This means I know I get a fax once a week, and that my fax number is staying active. I’ve included the link below to the one I use, but you can also just google “Weekly Fax Advertisement.”