Use the free image editor GIMP to open and edit PSD files (.psd > Photoshop)

Being free, open-source and covering the same range of features, GIMP is undoubtedly a great alternative to Adobe Photoshop. Furthermore GIMP gives you the possibility to open and edit PSD files out of the box, so that you can jump right in after installing the application. In Ubuntu you can install GIMP from the Ubuntu Software Center. Enjoy!