Your iPhone is a fantastic travel companion as it provides all the home comforts whilst you are away! Not only do you take a mobile phone abroad with you, but also your music collection, access to your e-mail, your family photos and videos, connectivity to the Internet and your Social Network connectivity.
The iPhone supports the UMTS/HSPDA network frequencies of 850, 1900 and 2100 Mhz networks as well as the GSM/EDGE networks of 850, 900, 1800 and 1900 Mhz. Most countries support these networks, so your iPhone should work fine.
Get a Roaming package from your Carrier