Gentoo's Live/Install CD uses very old kernel which doesn't have support for modern machines. Especially MacBook 3,1. Kernel 2.6.24 contains necessary module (sky2) for lan adapter shipped with this machines. Reproducible: Always
*** Bug 215975 has been marked as a duplicate of this bug. ***
I just updated the kernel in the snapshot-tree SVN repo, so it'll show up in 2008.0 Beta 2.
This should be fixed in 2008.0, which is now released.