Quenya is one of many languages invented by J.R.R Tolkein, famous as
the author of the Lord of the Rings books. My study of Quenya
came from information available on the web --see the ardalambion link
below-- and from Tolkein's own works, including materials published
posthumously.
I'm going to make a more comprehensive links section soon, but for now,
these two sites are connected to virtually everything quenya related on
the net.
best quenya website I've found:
Ardalambion
a fan community site:
the council of elrond
free, and they have excellent Quenya and Sindaran workbooks.