There are several. Ramble On mentions Mordor and Gollum, the Battle of Evermore directly mentions the Ringwraiths and has numerous other references, and Misty Mountain Hop mentions the Misty Mountains but is otherwise unrelated.
Battle of Evermore is the closest reference to LotR for the whole song, though; the others just mention LotR concepts relatively briefly.
Damage, Inc. - Metallica
Sentynel - Head Ninja, Admin, Keeper of the Ban Afrit, Official Forum Graphics Guy, and forum code debugger.
A still more glorious dawn awaits, not a sunrise, but a galaxy rise, a morning filled with 400 billion suns - the rising of the Milky Way