TUTORIAL: How to write in Elvish. This is the most detailed and thorough I've seen. Also, check out a lovely book called "The Languages of Tolkien's Middle Earth". It explains elvish (Sindarian and Quenya), Dwarvish, and others. Written by Ruth S.
When I hear LoTR fans saying this around a bonfire here in the UK for Guy Fawkes Night I always smile and shout MUSTER THE ROHIRRIM! Everyone who gets it laughs and shouts in response too, those that don't look at the rest of us like we're drunk or mad.