It works but not very well. I have to be sitting beside the router to get a decent signal. Have looked online for instructions on how to change the card, looks very complicated though. I was thinking of checking that it was seated properly but don't think I should attempt to carry out the proceedure. What would happen if I bought a USB WiFi dongle do you reckon?
The problem may not be with the airport card, more than likely to be the antenna in the display housing.
As these cables run through the screen hinge, they are subjected to constant movement and over time they become warn.
You could use a USB wifi dongle, I don't know how successful they are as I've never attempted to use one with any Apple product. I think the rule would be to find one that is compatible to your iBook.
I'm assuming your iBook is the G4 12" 1.33Ghz or the G4 14" 1.33/1.45ghz model.
In which case the Airport card is board mounted and would be difficult to replace.
I've had the privilege of replacing the antenna cables in the past on a G4 iBook. The only problem I found was getting a new cable. Secondhand cables may only be good enough for a short while depending on the use and quality. It's always better to buy something like that new. An Apple service repair agent should source and replace for you, but then you have the cost.
A USB dongle would seem the cheapest solution as these can be picked up for little money on auction sites like eBay.I had a Ubuntu laptop which run wireless from a USB dongle. I can't say it was very good signal wise as it had no antenna, but as it was Linux based, I can't say if the problem was the dongle or the OS.