Yachiro, there are many places all around the Internet and plenty of other interesting places where people find Oddworld Info. You have to remember that a) Oddworld's been around for some time, and there's plenty of stuff that's been remembered from years back, and b) there's a lot of adoring fans who always seem to stumble across this stuff.
To satisfy your curiosity a bit at least, you could check out Paul O'Conner's
Designer Diaries at Gamespot.
Incredibly,
Max Muggledarner