My name is XXXXX XXXXX I'd like to help you with your connection problem. I believe your saying that you'd like to connect your ibook G4 which is dead to your Macbook so that you can retrieve the information off of it, is this correct?
If the iBook G4 is dead, meaning that you can't get it to turn on at all then the only way to get the information off would be to physically open it up and then remove the Hard Drive and using a Hard Drive to USB adapter plug it into your Macbook.
I do not know how tech savy you are but if you don't feel comfortable doing this you can take the iBook to the Apple Store and they should be able to remove the hard drive and recover the information from it.
Please let me know if you have any further questions and don't forget to click the green "Accept Answer" button so that I may be paid for my service. Thanks.
The circle with a line through it means that there is a problem with the system folder on your G4. It is possible that the Hard Drive has crashed and that your data is no longer there.
You cannot hook the 2 machines up using an Ethernet cable unless you can get both machines to boot up and into the desktop. Since your G4 has a system issue you will not be able to do this.
On newer machines you can actually hook the 2 machines together using a Firewire Cable without the machine needing to fully boot, but the older G4's don't have that option if they don't have a Firewire port.
If the iBook has a Firewire port you could hook it up to another Mac that also had a Firewire port and then start the iBook while holding down the T key. This will cause the hard drive of the iBook to show up on the other mac and you can transfer the data.
Short of that you're only other option is to remove the Hard Drive and hook it up directly that that special adapter I mentioned before, or take it to the Apple Store and have them do it for you.