Unfortunately, the sonnet card only works with PCMCIA slots.
Your iBook doesn't have one of those.
It would work with G3 Powerbooks, but not with your iBook.
I have the same iBook as you, and the only solution is to find the old Airport card, but they're becoming more and more rare to find these days.
I don't think any cards exist of the airport shape made by other manufacturers.. as it's an Apple design that goes into Apple hardware.
Sorry 'bout that