You can try this, because I had the same problem with three of my iBook G4's. Basically, the newer iBooks had a loose connection between the Airport Card CONNECTOR and the logic board. It is no good trying to replace an Airport card, but there is still a "fix".
1. Open up the whole iBook until you can access the Airport Card.
2. Get some wood floor pad protectors from IKEA and stick one or two next to each other on top of the Airport card. There is a plastic bar (iBook 12") or metal bar (iBook 14") that runs across the Airport card and ends at the heat sink. REMEMBER TO SCREW THAT IN VERY TIGHT! It might take more effort than normal, but screw as hard as you can until it is fully screwed in. The plastic bar might bend a little, but that is just fine.
3. Reassemble your computer normally.
4. Zap your PRAM (Option+Apple+P+R) right after you hit the power button. Some of my iBooks don't chime during the PRAM resetting, so only release this key combo after you hear the optical drive sound for the 3rd time.
5. Your Airport should work just fine now.
In the case this still doesn't work, refer to these steps:
1. Turn off your Airport card immediately before your computer kernel panics. If you are unable to do this fast enough, boot into Safe Mode (Hold down Shift while pressing Power).
2. Boot back into your computer normally.
3. Go into Finder and find your computer's hard drive. Then, navigate to: /System/Library/Extensions/AppleAirport.kext
Delete these files and reboot.
4. You will no longer have Airport, so go and buy a wireless dongle for about $20 off Amazon.
Hope this helps!