eix - search tool for portage

Eix is the right hand of Portage.

How to install eix on Gentoo?

#emerge -av eix

How to use eix?

$eix keyword
(where "keyword" is any part of the name of the package you're searching for)

And eix finds you all the packages containing that phrase in their name, telling you the versions available, separating stable from non stable, and telling you which version of the program you're having installed already, if you're having any.

How to update eix?

(after you update your portage, execute the following command)
#update-eix

For updating eix together with portage, you can make your own custom commands that will update both portage and eix together.