Quenya-English
English-Quenya
Quenya Reverse Wordlist
The latter lists Quenya words written backwards, so that words that rhyme or have the same endings are grouped together (useful both for poets and for people studying Quenya derivational endings).
J. Sebastián Pagani has produced a PDF version of these wordlists.
Palatinus has also made a HTML version of the Quenya-English wordlist.
As for Tolkien's earliest "Qenya" as described in the "Qenya Lexicon" of 1915, no attempt has been made to include all of this material - partly because some of it is clearly not LotR-compatible, and partly because it is readily available in Parma Eldalamberon #12 (complete indices to the "Qenya Lexicon" are available on Ardalambion). However, the "Qenya" words cited by Christopher Tolkien in the appendices to The Book of Lost Tales, volume 1 and 2, are included in the wordlists here provided.
Offsite another PDF version (edited by Evenstar, website here) can be obtained: English-Quenya and Quenya-English, plus the Quenya Reverse Wordlist. These lists are as up to date as the RTF versions offered above.
For various neologisms coined by post-Tolkien writers, see Parma Penyanë Quettaron ("Book of Missed Words"), originally compiled by Boris Shapiro and now residing on the Gwaith-i-Phethdain site:
http://www.elvish.org/gwaith/ppq.htm
Compare Ales Bican's Newwords list, one of the original sources for Boris Shapiro's work:
http://www.elvish.org/elm/newwords.html