If you have a cell phone at home, check with your service provider before you leave to see if it will work from Mexico and how much it will cost. Chances are it may not work in Mexico, or it may be very expensive. It's relatively inexpensive to get a pre-paid cell phone in Mexico, such as Movistar. With this kind of service, you can call the U.S. or Canada and talk for 20 minutes for about 70 cents U.S. Most people find this to be the most affordable way to call home, and you can also use it for local numbers while you're in Mexico.
E-mail is a good way to stay in touch. If you have a laptop, we have wireless internet at Kukulcan.
If you're staying with a host family, be aware that you do not have the right to use their phone or computer, however for free you can connect to the house´s wi-fi.