Import of graphic files:

• grfguide - Documentation of the Graphics bundle: graphics, graphicx, color
  Describes inclusion and manipulation of image files, rotation and scaling of boxes and the use of color
• epslatex - extensive guide explaining how to use imported graphics
• l2picfaq - comprehensive guide describing how to include graphics
  german, english version in preparation

Creation of graphics:

• pgf/TikZ - powerful macro package for creating graphics,
  see manual
• PGF and TikZ examples gallery - great collection by Kjell Magne Fauske
• PSTricks - creating graphics using postscript
  see example collection and documentation
• Xy-pic - typesetting graphs and diagrams