It's there, Nick. . .check out the page on whistle keys.

xxx xxx g    Here is your key of G
xxx xxo a
xxx xoo b
xxx ooo c
xxo ooo d
xoo ooo e
ooo ooo f#

xxx ooo c    Here is the key of C
xxo ooo d
xoo ooo e
oxx ooo f (lot of variations on how you can play this note)
oxx xxx G or xxx xxx and blow a bit harder
xxx xxo A
xxx xoo B
xxx ooo C