Links (no paticular order)
Rare Witch Project - Hacked BK for the famous secret cheats.
Banjo Series - Making a game!
Banjo-Fella's Breegull Aviary - Again, making a game!
BK-Ultimate - Making a game.
The Mysteries of Banjo-Kazooie and Tooie - Some interesting ideas about the secrets.
Jagex software - AGAIN making a game. I mean They have over 10 games and theyre all done. Very nice site.