just do a search for mame emulator. There is an official site. The games are harder to find as they breach copyrights etc. There are quite a few sites out there that do offer them, again search for mame roms.
yeh just put in somthing like roms on google search and youll get loads of pages.. if youy look you will find it.. its not the finding its thecopying to disc thats hard espesiall things like iso files which are game files..