Chrome Extension
The Explain xkcd Chrome Extension is an open source Chrome extension that allows users to navigate from xkcd.com to the corresponding wiki entry by just clicking a button.
Installation
The extension can be installed here.
Usage
When viewing a comic on xkcd.com, click the Black Hat icon at the top right (where all the extension icons are located), and the explanation will be opened in a new tab.
Contributing
The source can be found on GitHub, under the MIT License.