I wish I had had “Rhyme & Reason”:http://rhymereason.net/ back when I was actually writing poetry. From the FAQ:
bq. Rhyme & Reason is a suite of online tools for poets and lyricists. It includes an editor for writing verse, an integrated dictionary, rhyming dictionary and thesaurus for finding words, metrical scanning tools for identifying meter and rhyme scheme, as well as features that allow you to share your work with others and comment on other writers’ poems or lyrics.
Now I don’t really give a damn about rhyming dictionaries and thesauruses–I already know too many words, who needs more–but I was always having to look up the metrical stuff (what’s the stress pattern in a “spondee”:http://en.wikipedia.org/wiki/Spondee again?), and having this done automatically would have been _excellent_.