I'll be traveling to France and Italy soon and have purchased a plug adapter for my cellphone and laptop chargers. This, of course, allows for the physical plug-in to a European outlet. Does anything else have to be done (e.g. convert 220 volts to 110, etc)?

No, phones and laptops are dual voltage so you have what you need.

That's NOT a completely safe assumption, raincitygirl . It's PROBABLY true in this case, but it's dangerous to make assumptions about electronic devices - and there's no need to. Every power adapter has voltage specs printed on it and you can see for yourself whether it will work at 220 volts. If the power adapter is truly "dual voltage" it should list a range of say 110 v to 240 v. (It may be in very small print. My trick if you can't read it: take a picture of the adapter print and enlarge the picture to read it clearly.)

I have destroyed one power adapter in Europe because I was careless: an adapter for a white noise box. I have another white noise box now - completely different make and model but this one too has the same issue: the adapter isn't designed to work at 220 volts, which I can now see in the small print. So now I use it only on batteries when I go overseas.

Thanks very much. My adapters say 110 to 240.

Then you are in good shape! You might want to bring along one of these to allow you to plug both in at the same time:

http://www.amazon.com/Philips-SPS103...dp/B005KSY9B8/

That one is out of stock at the moment. My local Dollar Tree carries them as well.

Okay Andrew, no need to get shouty.
I should have added, check the specs to make sure, but with phones and laptops these days it is usually safe to assume they have dual voltage. sandymel didn't say anything about white noise boxes, or hairdryers, or straighteners or other things that may not have dual voltage.