Hi. I've made an ebuild for Gentoo Linux for songbird-0.2.5. Maybe You'll add it to installation handbook at these page?
there is an ebuild

# Copyright 1999-2006 Gentoo Foundation
# Distributed under the terms of the GNU General Public License v2
# $Header: $

inherit eutils versionator

MY_PN="Songbird"
#MY_PV="$(replace_version_separator 1 '_' ${PV})"
S="${WORKDIR}/${MY_PN}"

DESCRIPTION="A multimedia player, inspired by iTunes"
HOMEPAGE="http://www.songbirdnest.com/"
SRC_URI="x86? ( http://download.songbirdnest.com/installer/linux/i686/${MY_PN}_0_2_5_linux-i686.tar.gz )
   amd64? ( http://download.songbirdnest.com/installer/linux/x86_64/${MY_PN}_0_2_5_linux-x86_64.tar.gz ) "
LICENSE="GPL-2"
SLOT="0"
KEYWORDS="~x86 ~amd64"
IUSE="alsa oss esd ogg flac faac musepack ugly theora speex ffmpeg gnome"
RESTRICT="strip"
RDEPEND="
   alsa? ( media-plugins/gst-plugins-alsa )
   oss?  ( media-plugins/gst-plugins-oss )
   esd?  ( media-plugins/gst-plugins-esd )
   ogg? ( media plugins/gst-plugins-ogg
      media-plugins/gst-plugins-vorbis )
   gnome? ( media-plugins/gst-plugins-gconf
      media-plugins/gst-plugins-gnomevfs )
   flac? ( media-plugins/gst-plugins-flac )
   faac? ( media-plugins/gst-plugins-faac )
   ugly?  ( media-plugins/gst-plugins-ugly )
   musepack? ( media-plugins/gst-plugins-musepack )
   theora? ( media-plugins/gst-plugins-theora )
   speex? ( media-plugins/gst-plugins-speex )
   ffmpeg? ( media-plugins/gst-plugins-ffmpeg )"
DEPEND="${RDEPEND}
   x11-libs/libXdmcp
   x11-libs/libXau
   x11-libs/libXfixes
   x11-libs/libXcursor
   x11-libs/libXrandr
   x11-libs/libXi
   x11-libs/libXrender
   x11-libs/libXext
   x11-libs/libX11
   dev-libs/liboil
   media-libs/gstreamer
   media-plugins/gst-plugins-base
   media-plugins/gst-plugins-x
   media-plugins/gst-plugins-xvideo
   media-plugins/gst-plugins-lame
   media-plugins/gst-plugins-mpeg2dec
   media-plugins/gst-plugins-mad
   >=sys-libs/glibc-2.3.2
    >=x11-libs/gtk+-2.0.0
    >=virtual/xft-7.0
    >=virtual/libstdc++-3.3
   x11-libs/pango"

src_install() {
   insinto /opt/songbird
   doins -r *
   fperms 755 /opt/songbird/Songbird
   fperms 755 /opt/songbird/xulrunner/xulrunner
   fperms 755 /opt/songbird/xulrunner/xulrunner-bin
   dosym /opt/songbird/Songbird /opt/bin/songbird-bin

   newicon ${S}/chrome/icons/default/default.xpm ${PN}.xpm
   make_desktop_entry ${PN} ${PN} ${PN}.xpm "AudioVideo;Player"
}

pkg_postinst() {
   echo
   ewarn "Songbird is still under development!"
   einfo ""
   einfo "If You need other music/video plugins, look at"
   einfo "Your portage tree into media-plugins/gst-plugins-*,"
   einfo "but remember, that not all plugins are supported yet."
   einfo ""
   einfo "If You don't want too much deps on these package,"
   einfo "disable gnome support"
   echo
} 

You have to insert it into /Your/portage/overlay/media-sound/mozilla-songbird-bin/ and make digest by
# ebuild mozilla-songbird-bin-0.2.5.ebuild digest

oh, If you have too much deps for compile, look if you have enable gnome flag for these package, because gnome flag are compiling gst-plugins-gconf and gst-plugins-gnomevfs, which need a lot of stuff from gnome.

Maybe someone will use it

cheers!

I've set up CVSWeb on the Windjay source server for the Songbird extensions.

I've also set up anonymous CVS access at the following address:

:pserver:anonymous@windjay.com:/ftp/pub/cvs/windjay

The eMusic extension at extensions/EMusic is the most basic of the extensions as it doesn't use any special XPCOM components.

The iPod extension at extensions/IPodDevice provides an example of a cross platform C++ XPCOM component. It builds for Windows, Mac OS/X, and Linux. It also makes use of the libgpod library at ext/libgpod.

I'll be writing up some instructions for building the extensions. I'll also be working to make the build simpler.