international calls can be made from public cardphone booths and kiosks
(periptera) equipped with meters.
Some neighborhoods with a large foreign population have phone centers.
Telecards which have exceptionally cheap rates can be purchased from
kiosks, international phone centers and OTE offices and these can be used on any phone, even your hotel and you will just be charged for a local call which in most hotels are free. See Phone Cards
For information on renting cell phones see www.greecetravel.com/phones
Another way to stay in touch is bring your laptop and have skype. Those who use blackberries or their cell phone from home should be aware that there may be roaming charges and your phone bill may cost more than your flight to Greece. Especially on the border islands where you may unknowingly be on the Turkish network and be paying roaming charges of about 5 euros a minute or more. This also goes for mobile internet for your PC that uses GSM frequencies.
The best thing to do is stay at a hotel that has free wireless internet for your iphone or laptop and free computers to use. I recommend the Hotel Attalos
See also Staying in Contact
Athens Practical Info Index