get a dumper
dump rom
the most well-known (reliable) source would be lik-sang, although they are tad expensive there, and they love to rip you off
but i agree with xeno... unless you plan on ripping something no one has ever dumped before, like one of them limited edition carts or something, it's better to get what's "out there already," assuming you already own (in physical form) whatever rom you plan on getting..