I received a pointer to the Visual Thesaurus in response to my web visualizations post and I had to blog about it.
Thanks for the link, Carla! Take a look at the visual thesaurus at http://www.visualthesaurus.com/.
Enter a word and it shows synonyms with lines, and antonyms with dotted lines, plus when you put your mouse over a word a definition is displayed. And it offers audio pronunciation recordings. This tool is perfect for writers, and I’m sure has proven useful for teachers and English as a second language students.