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

Unicorns of the Vale: Home of the International Firebringer Appreciation society, or IFAS ...
Unicorns-of-the-Vale: A Firebringer Trilogy fan group @ deviantART
Skywater's Mere of the Moon
Scylla's IFAS Grotto
Calydor's Firebringer Oasis
Before the Flame: an FT RPG group set in a time when Sa is still just a nursling ...

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.