Step 21 (Final Network Configuration). The instructions are well hidden in this step. Since the liveCD detected my network card and accessed the internet without a problem and I copied settings to my gentoo installation, I assumed the network configuration was OK. Not true. The /etc/conf.d/net needed to edited to add "dhcp" to the configuration. It took me awhile to find this.
This is clearly mentioned in http://www.gentoo.org/doc/en/gentoo-x86-install.xml#doc_chap21_sect2 (obsoleted document) and http://www.gentoo.org/doc/en/handbook/handbook.xml?part=1&chap=8#doc_chap3_sect2. Both documents explain that "dhcp" is for automatic IP retrieval.
