I just came across a group at the Kyoto Notre Dame University who are building small text utilities called, Personalized Online Electronic Text Services (POETS). They have a nice English Vocabulary Assistant (EVA) WordNet 3.0 Vocabulary Helper which takes a word, looks it up in WordNet and gives you an exhaustive entry. They also have a Eva Text Analysis service that will, for example, link all words in a text except for stop words, to the Vocabulary Helper entry.