<< Anyone know how to use a computer faxing without a dialup modem (ie I have cable internet)? >>
Like bsobel says, you'll need to use a web-fax service. Dialup modem faxing makes an actual phone call to another fax machine and sends "fax data" to it. It does not use your internet provider or the net. There's no reason I suppose why you couldn't also just buy a $20 modem and install it for faxing.