Using Extended Character Glyphs in Illustrator

Illustrator ships with a variety of OpenType Fonts which often have a myriad of extended characters (also known as glyphs) that can add real flair to your layouts. There are also many OpenType fonts for sale online. But how do you access these extended characters and glyphs?
• Part 1: Using the OpenType Panel in Illustrator CS5
• Part 2: Using the Glyph Panel in Illustrator CS5