Links

Shinjiru Kokoro - a very pretty general combo site
Tenacity - MKRE collective featuring a general TV series site, OAV site, and shrines for Eagle Vision and Clef
Cephiro - believed to be the oldest Rayearth site (and still around!), created in 1995 by "Fuu" aka Rika Takahashi, a prominent member of the CLAMP fan community turned professional translator. This site has all sorts of information about the manga, show and merchandise that only someone following the series when it was on in Japan could provide. Rika Takahashi created fan translations of the MKR manga and anime before it was commercially licensed, and in a neat turn of events, also provided the official English translations for both the Tokyopop manga and Media Blasters anime release.
Magic Knight Rayearth Image Gallery
MKRE LiveJournal Community
Magic Knight Rayearth Dimension - general combo

In My Heart: Magic Knight Rayearth