Thankfully most wall adapters are showing up are what is known as "free voltage" designs capable of using 100 to 240 VAC and 50 or 60 Hz. That means you just need those plug adapters.
Such are widely available and your tourist hotels will sell, loan or rent such to you.
I was wondering what people did when they traveled abroad and wanted to charge their digital camera battery (proprietary battery, not disposable battery). I have a Canon Powershot SD300 and am traveling this summer. I am considering getting an adaptor for different voltages and outlets but this seems a bit much. Is there any other way (charging through USB cables, maybe?) If it comes down to adpators, which adaptor is good (and cheap, I guess)?