To run World of Warcraft on a Gentoo system, you will need, at the very least, an X server, graphics drivers, and wine.

While any version of Wine will work to an extent, it's better to use the newest Wine package available in portage.

As of this writing, the newest version of Wine is 0.9.45. This version provides many performance benefits over previous versions.

This same principle carries over for video drivers. If you own an nVidia or ATi video card, you should consider unmasking and installing the newest drivers available in portage.

If you are working with a non-standard configuration and find that you want to attempt some of the patches mentioned in this HOWTO, you will need to create a portage overlay. If you are not familiar with this process, please read Create an Updated Ebuild.

 You are best checking this page out for more info as its a pretty messy install

http://gentoo-wiki.com/HOWTO_Install_and_update_World_Of_Warcraft_with_wine