Actually, the whole ROM thing is one heck of a grey area that I hate. I usually consider them illegal through and through.
Here's something off of the Nintendo website.
Can I Download a Nintendo ROM from the Internet if I Already Own the Authentic Game?
There is a good deal of misinformation on the Internet regarding the backup/archival copy exception. It is not a "second copy" rule and is often mistakenly cited for the proposition that if you have one lawful copy of a copyrighted work, you are entitled to have a second copy of the copyrighted work even if that second copy is an infringing copy. The backup/archival copy exception is a very narrow limitation relating to a copy being made by the rightful owner of an authentic game to ensure he or she has one in the event of damage or destruction of the authentic. Therefore, whether you have an authentic game or not, or whether you have possession of a Nintendo ROM for a limited amount of time, i.e. 24 hours, it is illegal to download and play a Nintendo ROM from the Internet.
I'm pretty sure that it isn't just to Nintendo games that they say this for, but that this can technically be extended to other areas as well, but that's just me speaking as I don't like the idea of ROMs.
Edited by scff249, 23 February 2009 - 01:28 AM.
"Ototo'i wa usagi o mita no...Kino wa shika...Kyo wa anata." -Kotomi Ichinose (Clannad) [see below for translation]
"Day before yesterday I saw a rabbit, and yesterday a deer, and today, you." -The Dandelion Girl
"You are not alone, and you are not strange. You are you, and everyone has damage. Be the better person." -Katawa Shoujo