GIMP – The FREE Open Source Photoshop

For those who might not be familiar with it, there is a free alternative to Photoshop called GIMP – The GNU Image Manipulation Program which is surprisingly powerful and useful, and has a tonne of plugins and tutorials out there. I've been using it in lieu of Photoshop recently (since I can't afford the $600 for Photoshop at the moment just to do some minor photo editing) and so far I've found it quite easy to use and well documented.