"Privately operated fax facilities are ubiquitous (common), especially in Third World countries. Sending a fax is often cheaper than making a telephone call, because it takes less time. But you do not have the convenience of getting an immediate answer and some hotels, etc. may not want to pay to send you an answering fax." <Larry Cotter>
One thing I did, when I was in a place long enough and had access to phones at hotels, was to fax (or email) home with the phone number and times I would be available, then ask them to fax back when they would call. With today's callback services, and overseas calling cards, this may not be necessary.
"Obtain fax numbers of everyone you might need to contact, including banks. Carry with you and leave a copy with your contact at home. You can also have your contact at home save you money by forwarding copies to other parties as you direct. Let them know that you are charged by the page for return faxes, so they should skip cover pages and type small, but not too small. A silhouette-type drawing cut from a brochure copied onto your fax will make it feel more personnel to your recipients." <Scott Soper>
There are also email-to-fax services available on the net. A few places to start are: FAQ: How Can I Send a Fax from the Internet? and Best Online Fax Services