The original premise of the series was about a trio of teenage musicians but later evolved into about teenage secret agents.
Was originally produced by Saban, but was temporarily shelved after season one because it was thought to be too close to Disney's Kim Possible (2002). Coincidentally, Disney later bought the rights to the series themselves.
WOOHP, the secret organization that the girls work for, stands for World Organization Of Human Protection.
Alex Huang was originally Shanghaiese before they made her Chinese/Kazakh.
When Cartoon Network started to air these episodes, the original season one opening sequence was dropped, and the second season opening sequence is what is used.