There is a video talking about how to build a data list for your favorite fax broadcasting software.
How hard could it be to build a fax data list using mysql, MS Access etc
Company Name, Fax Number
ABC Co, 15065551212
XYZ Co, 17025551212
That's it.
You just have to make sure that you've put commas on the fields if the software asks for it.
Honestly.. this is the cheapest way to communicate with your existing client list. Why pay 45ยข for a stamp and printing when you can just send them a fax!!