Meet the Gimp by Rolf Steinort features video tutorials on the GIMP, an alternative to software like PhotoShop and Fireworks.

screencasters.heathenx.org by HeathenX and Richard Querin features video tutorials on Inkscape, a vector graphics program similar to Adobe Illustrator, Corel Draw, or Freehand.

Both programs are free software and run on Linux, Mac, Windows and BSD.