It's some tricky stuff. But thankfully this issue is a lot simpler: The Timbaland-produced Nelly Furtado track "Do It" is, for all practical purposes, "Acidjazzed Evening" by Tempest, with some of the instruments changed, and a vocal track added. Of course, I can't link you to the Timbaland/Nelly Furtado version, because that would be stealing.
Of course, most people don't know who Tempest is... Which is understandable, since he's from Finland and does most of his music in Amiga MOD format, and Timbaland sampled a (sanctioned) alternate version for the Commodore 64. And I have to imagine that Timbaland (or one of his assistants) figured that made it okay... And he might have gotten away with it, too, if it weren't for you damn kids and your Amigas and/or Commodore 64s!
Apparently the original yoink of the music was when it was distributed (for profit) as a "hot original" ringtone, "Block Party". Which was even more blatant, since it was just AcidJazzed Evening with a non-bleepy drum sample. Then later, they decided to make it into a Nelly Furtado track, though again they forgot to, you know, change it all. It's clear that this isn't even a cover; The programmer of the Commodore 64 edition of the song was able to recognize very specific bits and pieces of his arrangement of the track, the sort of stuff you only know if you write your music by hand, in assembly code.
The story is all over the place, though, and Tempest does have a lawyer, so I expect this will result in some kind of a settlement for him.
I found it very amusing, though, given all the recent bitching about how "video games aren't art"... Not that I took that arguement seriously to begin with, since video games are literally made of art, graphical and otherwise, but it's neat to see that even the trilling, bleepy, staticy game music of my youth has become part of popular culture, legally or otherwise. Even now, frat boys' girlfriends are shaking their booties to finnish computer nerd music!
Lots of additional info and links here if you're interested, including a funny/incriminating/photoshopped picture of Timba himself. (He does not actually wear a C64 on a gold chain, but it is known that he has a SIDStation, a rare and specialized piece of hardware used to professionally mix and record Commodore 64 SID music, in his studio. Which doesn't do much for the "It was all an accident" theory, unless legally-impaired studio interns are involved.)