the previous respondant is right - as long as it's not for sale or public consumption. You are only trying to sell your skills as an artist, animator, etc.. And as long as you're using someone else's work as inspiration, you might as well be the chump, and give a link to where other people can find a way to look at, listen to, or even purchase the original source of inspiration. [Britney doesn't need the help, though, and K-Fed doesn't deserve it.]
Where it does get very tricky is when you try to copyright [U.S. terotories I'm speaking of here, now] your own work, because THAT is where you need to get legal permission from a company, individual, etc. Question 6 on the copyright.gov forms about derivatives is a b*&*!d!! You must also be clear about when you've done work-for-hire and maybe are using some other studios' project that you worked on. Seriously, ask the source instead of the phone people in Washington D.C. - I found them for the most part, to be an incredible waste of my taxpayer dollars when it comes to legal specifics, because I got 3 different answers from 4 different phone reps.
I myself am going through this with artwork that I drew from by eye, but didn't even use beyond the so-called 'inspiration' factor. I am having to check with company lawyers who deal with [remember-this-word] [b]PERMISSIONS[/b] . That is who and what you ask FOR. [My friend, a lawyer, told me so.]
What I can recommend is that musically speaking, there are websites with copyright free pics,music, etc., and a good soundeffects website that I recommended before, http://www.sounddogs.com/ - --
At this site, you can test any number of sounds using their search box, and then if you like the sound enough to use it, it's cheap maybe $5, and you're in the clear. And seriously, mixing your own stuff shows a lot of initiative, if you can time the stuff out on soundforge, in AE, Flash, etc. If you believe in happy accidents, this is the place to find them. It'a an incredible resource.
Art and music used in personal websites isn't seriously policed really until you try to protect your own stuff because there is so much out there, and then it gets weird and legal. [Unless you're using the song "Happy B-day To You", I heard those guys are...and for the record, Irving Berlins' estate donates all of the royalties monies to the Boy Scouts of America].
I recently found an article in the NY Times regarding more flexible copyrights, and I will post that info later on this week when I actually have the article itself in my hot little hands. But until then, still have some good info here that I myself have been given. Anyone else?
Any copyright lawyers out there slacking off and looking at CG websites instead of reading legal briefs?