Just arrived from Greece and I must say that the Cosmote 3G service is perfect, with great coverage in all of the areas visited (Athens, Delphi, Arachova, Lefkada, Metsovo, Meteora).
Bought a Cosmote Internet On The Go On Request SIM for 20 €. You must activate the service via the web page
http://ciotgonrequest.cosmote.gr:80/...Label=HomePage where you can choose different topping options.
You can buy the SIM card alone for 20 € or in a bundle with a USB 3G modem for 50 €. I decided to go for the first option because my iPhone 4 can act as a 3G modem and a Wi-Fi Hotspot.
The SIM card is only for data, it doesn't include any voice service and you can't make any kind of voice calls, event to greek numbers. It's intended to be used installed on USB 3G modems, tablets like the iPad, but you can use it perfectly with your iPhone. You can any other old mobile phone to put your SIM card into it and use it for voice service.
The SIM card can be purchased in a MicroSIM edition, fitting perfectly on Apple iDevices. I have used it both on my iPhone 4 and my 1st generation 3G iPad and run flawlessly.
With the purchase you get 20 € of credit that you can spend buying different combinations of data and duration. I found the 10 days / 3GB combo the best solution; it gets 15 € off your credit and you get 5 € so if you run out of data you can top it with the extra 5 € and you'll get 1 GB more.
So it can actually be used for 10 days with up to 4 GB of data transmission, more than enough for most users. I barely used 800 MB in 7 days of use.
