here is a download for the newest version of the n64 emulator for xbox called Surreal64 CE B6.1 Beta r342.
also included in the download is a full USA N64 romset and the japanese game sin and punishment.
i have also included the boxart for the games as well,they will be displayed when you scroll through the romlist.
there is also different skins for you to choose from.
to play on a modded xbox just unrar and ftp to your xbox hdd or use qwix 101 to make a xbox iso and then burn to disc.