220 Volt AC in Germany
If you want to operate devices which you bring from your home country, such as notebooks, mobile phone, battery chargers for cameras, camcorders, etc, then you must study the manual of your device or its power adapter in order to find out if it is able to digest 220V. Notebooks and phones as well as camera battery chargers usually fulfill this requirement because they are meant to travel.
However, what they do not provide is the correct plug and you will need a travel adapter. Such thing will not convert any current but just adapt to the plug of the specific country.
Usually you buy these Travel Plug adapters in electronic stores or department stores. Examples in the U.S. are Radio Shack and Best Buy as well as Target and Walmart. You can also buy them online, e.g. on Amazon.com.
In the pictures above you can see such International Travel Adapter. The Universal Travel Adapters offer plug combinations for several countries and their advantage is that they are universal but their weight is a little bit more than a single specific plug for one specific country.
Another good idea is to take a small power strip with you for using multiple devices at once and also has a longer cable.