GIMP (which stands for GNU Image Manipulation Program) is a free image editing program that can be used for a range of purposes, including creating icons for the resource sites and sprite sheets for The Spriters Resource. It is available for Windows, OS X and Linux at www.gimp.org.
|2D||Microsoft Paint - GraphicsGale - Adobe Photoshop - Paint.Net - GIMP|
|3D||Autodesk 3DS Max - Autodesk Maya - Blender - Cinema 4D - Milkshape 3D - Anim8or|
|Sounds||Adobe Audition - Audacity|