The below document link for download is from a class at the 2003 Autodesk University. The document was originally written for AutoCAD 2004 and the Tool Palette Extension but is applicable to AutoCAD 2005 as well.
Make the Most of Tool Palettes in AutoCAD® 2004 and Beyond
By: Heidi Hewett
Use tools and techniques to quickly add existing block and hatch content to AutoCAD® tool palettes. In addition, you will explore the most recent tool palette functionality, as well as a few other surprises that are only available through the AutoCAD 2004 extension or AutoCAD 2005. To manage these powerful tool palettes, you will practice techniques for easily sharing and accessing multiple tool palettes.