Darktable is the free equivalent of Lightroom. Its an open source photography application and RAW developer. You can download it
at http://www.darktable.org/install/.
Sadly there is no Windows installation out of the Box on the Website but you can download a Ubuntu live CD with Darktable installed.
My first impression of Darktable was that it look really familiar to the Adobe Lightroom 4.
Darkroom is available in several language which are automatically detected depended on the Operation System language.
The modular workflow has three main sections, the Lighttable, Darkroom and Tethering.
In the Lighttable Module you can organize your images, Meta-data can be viewed and changed. You can categorize and sorting your images in a variety of ways.
The Darkroom module is for the manipulative work. All effects, corrections and related functionality is not destructive and the result is often better then what can be achieved
from a “professional” software.
The Tethering module is used to connect your cameras to Darktable to import the images automatically.
Darkroom is nice to handle, comfortable, fast and the results are really high-end. And the best is that Darkroom is completely free.
Just get it, its worth to have a look on it and then spend the saved money on a good Dinner with your girlfriend or wife(whoever you like more).