doady: Emulators or the use of emulators are never illegal. The only thing that's illegal is some fo the methods games are obtained, and that applies not only to console games but also PC games as well. There is nothing illegal about either emulators and ROMs, only certain methods that ROMs can be obtained.
As I said, it renders -most peoples- use of emulators illegal :p
Technically, that's not100% true, I admit. It's a somewhat questionable area as to if the use of something which is legal, to run something which is not legal, is legal or not in and of itself.
There are legitimate ways to obtain ROMs, yes. However, 90% (or more) of the people who obtain them, are not doing so legally. There is no "grey area" that makes ROMs legal when you do not otherwise have legal rights to duplicate, use or distribute the copyrighted material. Things like that are just ways people try and justify copyright violation. :p
(That being said, I think copyright laws are somewhat insane, and should either expire sooner, or work such that if you stop doing anything with the copyrighted materials for X amount of time, you lose the copyright. Thus, a best-selling author would keep his copyright to his book because it was continually being printed and sold. But a nobody schmuck author who wrote a book and just left it alone for 10 years because no one wanted it, wouldn't.)