These ebuilds come from http://github.com/sjnewbury/multilib-overlay.
If you have some problems, go to the official site first.
bzip2 : A high-quality data compressor used extensively by Gentoo Linux ( http://www.bzip.org/ )
libarchive : BSD tar command ( http://code.google.com/p/libarchive/ )
lzma-utils : LZMA interface made easy ( http://tukaani.org/lzma/ )
xz-utils : utils for managing LZMA compressed files ( http://tukaani.org/xz/ )
Add an ebuild in portage :
The ebuild is now in the portage tree.
You can also use layman : emerge layman then layman -a multilib
For Paludis use this rsync : rsync://gentoo.zugaina.org/multilib-portage
If you have a problem : ycarus(-at-)zugaina.org