A few days ago I blogged about a conflict problem I was having with Firefox 3 on my Gentoo box. I did some further searching on the internet and found a fix on one of the mailing lists that caters for Gentoo topics.
Essentially, to fix it, you need to alter the /etc/make.conf file and alter the USE flags so that it includes the following:
USE=".... -firefox xulrunner ..."
$ emerge -DNuva --with-bdeps y world
and everything should be right. This will also recompile anything that was using Firefox 18.104.22.168 as a basis, and convert it over to Firefox 3.0.5. Apparently the package support was split out some time ago, and I missed the announcement.
Everything else is running smoothly...