dosbox : DOS emulator ( http://dosbox.sourceforge.net/ )
mame : Multiple Arcade Machine Emulator ( http://mamedev.org/ )
nestopia : NEStopia is a portable Nintendo Entertainment System emulator written in C++ ( http://0ldsk00l.ca/nestopia/ http://rbelmont.mameworld.info/?page_id=200 )
pcsx-df : GNU/Linux fork of the discontinued PlayStation emulator PCSX ( http://pcsx-df.sourceforge.net/ )
retrocopy-bin : RetroCopy is a multiple home and arcade system emulator and media player ( http://www.retrocopy.com/ )
virtualjaguar : an Atari Jaguar emulator ( http://www.icculus.org/virtualjaguar/ )
Add an ebuild in portage :
The ebuild is now in the portage tree.
You can also use layman : emerge layman then layman -a paddymac
For Paludis use this rsync : rsync://gentoo.zugaina.org/paddymac-portage
If you have a problem : ycarus(-at-)zugaina.org