HTC Eris :: How To Do A Fax With Phone

So I have ran into a sort of a dilemma, there are at certain times that I need to have access to a fax machine, which I do have a All-in-one printer, copier, scanner fax machine. But without a land line it makes the fax part sort of useless, so I know on some older phones I could use my phone as a 56 K connection, so I was hoping I could either hook my phone up to my computer and using the phone as a modem to do a fax from within windows. Or if their is a app in the market to do it. I do have a fax machine at work, but I don't want to use it unless I absolutely need to.

Any one have any suggestions on how I can go about doing thing?