Links to all things Tolkien
Sindarin 
Ardalambion ~ The best source of information about all of Tolkien's invented languages anywhere; absolutely essential. Includes an online course for learning Quenya.
Hiswelókë Sindarin Dictionary ~ An essential tool for students of Sindarin.
ELFling ~ An email discussion group for all Tolkien languages.
Mellyn in Edhil ~ Audio files of the Corpus texts, a Sindarin phonology guide with audio samples, Sindarin Phrases for role-playing, original compositions, tengwar, etc.
Gwaith i-Phethdain ~ Everything about language in the movies, essays on grammar, samples of calligraphy, and more.
Tain e-Lam Thindrim ~ Home of the Smiths of Sindarin with translations.
Amanye Tenceli ~ How to write in tengwar, the script of the elves.
Dan Smith's Fonts ~ Fonts for writing in tengwar and cirth (runes).
Indûr's Language Links Page ~ For more useful links.
Tolkien's Middle-Earth
The Tolkien Fanatics Plaza ~ A great community of fans with discussion forums, role-playing, quizzes and more. You'll find us in the Language Forum!
The Encyclopedia of Arda ~ Factual information on everything in Tolkien's world from A to Z.
Maps of Middle-Earth ~ A huge collection of maps, includes Beleriand and the journey of the Fellowship.
The Council of Elrond ~ Films, forums, fans, photos, etc.
Art by J.R.R. Tolkien ~ pictures by Tolkien himself, including his tengwar and heraldic designs of the Elves.
Edoras - The Tolkien Art Gallery ~ A fine collection of Middle-Earth artwork by the likes of Alan Lee and John Howe.
The Lord of the Rings Movies
The Official Site ~ with behind-the-scenes information and extras.
JW's LOTR Site ~ Transcripts (with screen captures) of the movies.
The One Ring ~ News, pictures, articles, etc.
Middle-Earth Fan Fiction
The Mellon Chronicles ~ An excellent series of fanfics about the friendship between Aragorn and Legolas.
The Very Secret Diaries... ~ Very funny, for mature audiences.