As of July 2015, good charts of the Greek alphabet are online at Pennsylvania State University Libraries, Sky and Telescope, and About.com. Penn State's chart is a transliteration table that shows each Greek letter, its English equivalent and its character name. Some letters have specialized notes, as well.
Sky and Telescope's chart displays capital and lower-case symbols for each Greek letter and its name. Every name has a link that allows the user to hear its pronunciation based on the American Heritage Dictionary. About.com exhibits the names of many Greek letters, their symbols and their HTML codes for individuals who write about science or mathematics online.