We're actually supposed to ask the author/composer/artists/whatever about credits, it's actually illegal to list someones name without permission. Sometimes the artist will provide the name, in a license document, which we can assume means that they would want that name used in any credits.
So, to keep yourself right, check for documents that might specify the artists requirements for credits, if you can't find any, then just don't credit them. You might be able to get the name from the MP3 file, but you have nothing to say that the artist wants to be named, you have nothing to say that the artist wants to be associated with you or your product, so it's somewhat illegal.
I say somewhat illegal, because in most cases of course - the artist isn't going to mind his name being used - we just have to consider this stuff in case it bites us in the butt later. For instance, my game project uses 5 songs from 5 different authors from a well established soundtrack site. Now these soundtracks cost like £30 each, and are publication quality - they wouldn't sound out of place on TV or in a film, in fact a lot of TV adverts use sites like that. Anyway, the composers name is shown on the website when previewing the tracks, so I just used it from there. The artist provided their name and they wouldn't do that if they didn't want to be credited. So I credited the website and each musician by name, even though I'd be fine just crediting the website, or even not creditting anyone. I'd say, if it's not obvious who the composer is, then don't credit them, just credit the copyright holder instead, like The Game Creators for instance.
Health, Ammo, and bacon and eggs!
