The following are sites related to the Firebringer Trilogy and Meredith Ann Pierce ...

Unicorns-of-the-Vale: A Firebringer Trilogy fan group @ deviantART
Unicorns of the Vale: (@ msn) Home of the International Firebringer Appreciation society, or IFAS ...
The Hallow Hills/Children-of-the-Moon
Skywater's Mere of the Moon
Scylla's IFAS Grotto
Calydor's Firebringer Oasis
The City of Fire: an RPG group about the city of the Firekeepers that imprisoned Jan in Dark Moon ...
The Divine Star Valley: an FT-inspired RPG group set in a fan-created realm on the world of Alma ...
Before the Flame: an FT RPG group set in a time when Sa is still just a nursling ...
Children of Alma: another FT fan-group ...

Got a link?

Moon and Unicorn: the Official Website of Meredith Ann Pierce
Firebird and the Firebringer: Wolfen "Alayha" Moondaughter and Tori "Skywater" Morris' interview with MAP
Firebird Books: website for the Penguin imprint that has reprinted FT.