I use the GNU Image Manipulation Program (GIMP) for editing my photos. GIMP is an open source project that is very similar to Adobe's Photoshop. Being open source, the GIMP is free to use instead of costing hundreds of dollars (or breaking the law to run a cracked copy.)

Links: GIMP home page GIMP Download page

As this website builds, I will be working on some guides and tips/tricks to put here.