This is an ideal laptop to run Linux on. First, the Apple hardware design is killer. The look yes, but also the speed (the 512k L2 cache helps alot), feel, ergonomics, battery life, display etc, etc are all excellent.

It runs 99% under the 2.6.x kernels (I haven't tried any previous kernel versions personally). The Radeon driver and DRI in the 2.6 kernels run the vid card just fine, the Airport uses the hermes module (note: this is the 'original' Airport. Airport Extreme is not yet fully supported at the time of this writing).

I gave it a 9 rather than a 10 because of two small issues: The tv-video out isn't completely functional under Linux (yet), and I am only able to hear sound output from one app at a time. I haven't invested much time in either issue, but some other experienced Gentoo-iBook users have reported the same thing with no obvious solution. I imagine the sound problem can likely be overcame by use jack or dmix maybe? Otherwise this thing is great. I get over 4 hrs on one battery (3 playing dvd's) and since sleep works perfectly on this kernel you can carry it (running) forever with the lid closed and not use up the battery.

*note: the battery life above is on a 12.1". Larger models are likely to have less battery life.

If planning to install Linux on an iBook, Gentoo or otherwise, this page will be an invaluable source of information: http://www.desertsol.com/~kevin/ppc/

$lsmod output:
Module Size Used by
radeon 132796 2
snd_seq_oss 39320 0
snd_seq_midi_event 7264 1 snd_seq_oss
snd_seq 59800 4 snd_seq_oss,snd_seq_midi_event
snd_seq_device 8132 2 snd_seq_oss,snd_seq
snd_pcm_oss 64260 0
snd_pcm 108436 1 snd_pcm_oss
snd_page_alloc 10980 1 snd_pcm
snd_timer 24352 2 snd_seq,snd_pcm
snd_mixer_oss 19904 1 snd_pcm_oss
snd 52612 8 snd_seq_oss,snd_seq_midi_event,snd_seq,snd_seq_device,snd_pcm_oss,snd_pcm,snd_timer,snd_mixer_oss
airport 5984 0
orinoco 50924 1 airport
hermes 13632 2 airport,orinoco
sungem 32928 0
sungem_phy 9664 1 sungem
i2c_keywest 11464 0
dmasound_pmac 91172 0
i2c_core 24420 2 i2c_keywest,dmasound_pmac
dmasound_core 20432 1 dmasound_pmac
soundcore 8736 2 snd,dmasound_core