Tolkien Gateway is a friendly starting wiki, including the tree of the Elvish languages
Wikipedia's Elvish languages (Middle-earth) has some value.
Glǽmscrafu: Tolkien's linguistic cellar
includes "A! Elbereth Gilthoniel!" read by Tolkien himself and other similar.
Ardalambion: Of the Tongues of Arda, the invented world of J.R.R. Tolkien
includes a Quenya Course and excellent Quenya Wordlists
Ardhon Ellammath, the Realm of the Elf-languages has many recordings by many readers.