You need a special charger and plug adapter for most countries. No big deal, as most elctronic stores like Frys sell these "world" kits.
Before you leave for Europe, make sure:
1.) That your phone is unlocked (if not, call your provider to give you the unlock code).....this will enable you to buy prepaid SIM cards in the country you're in which will give you MUCH CHEAPER rates than your US SIM card (i.e. 8cents/min vs $1.50+/minute).
2.) That your provider allows you int'l roaming. Providers like Cingular, etc need to enable Int'l roaming function. Your SIM card should be activated for Int'l roam, just in case you're in an area where you can't secure a prepaid SIM card (which is nearly impossible in cell crazy Europe).
Also, be aware that cell phones pound for pound are markedly cheaper (even with the expensive Euro) and much more advanced than US models. Europe always have the LATEST models. You could look into getting a new phone while over there...like I did. 😀