I work for a mobile phone network in the uk. If your planning on taking your mobile abroad with you call your network Provider to check roaming call charges a few days before you leave. The company I work for offer a fantastic roaming bundle for a small price compared to normal call rates. Some accounts need things added to them (free) to insure they will work abroad (don't always assume)....Also my companys Insurance will cover your phone world wide and it will usually be replaced within 24 hours of You bein back in the uk, unlike banks and travel insurance who want you to prove many things. I have seen this so many times....
Also I know people will know this already but you'd be shocked how many people don't, if you loose or your phone is stolen you must report it to the local police asap. Also where possible call your network provider and get the sim barred so your not left sortin a big bill!!