Well, the Rahman version of the song was played over the ending credits of Slumdog Millionaire, both song and film winning Oscars a couple of weeks ago. According to Wiki, it was Ron Fair of Geffen Records who had the idea of getting Rahman and Scherzinger to come up with a new version of the song for the U.S. market. Anyhow, Rahman and she worked on the new track together (the fact that she's being credited specifically probably means that she was the only Doll actually to make an appearance, and an article by the Times of India makes it seem as if "Pussycat Dolls featuring Nicole Scherzinger" means Nicole Scherzinger period*); "Nicole says the song shouldn't be called a remix, but an interpretation. 'I wanted to maintain the integrity of the song, but also play on the sexy beats that he's used.'" In other words, the melody she sings isn't close to the melody of the original.

(I'm not sure, since I'm relying on Wiki here, whether the Billboard ranking combines downloads for both the original and for the PCD's version - Wiki is saying that the soundtrack version got over 100,000 downloads last week while the PCD's version got only 27,000, which means that Billboard ought really to be crediting the original not the PCD's, though maybe it's the PCD's version that is racking up airplay points.)

*But then, that could well be true of a lot of Pussycat Dolls songs. I've never made much of an effort to understand the concept of the Pussycat Dolls; they were a burlesque group for seven years before becoming a pop group and adding a couple of people - Nicole Scherzinger and Melody Thornton - who actually sing.