Here is Kapoor talking about his sculpture:
http://www.youtube.com/watch?v=An60H5a1OMs
and some information on the selection process,
http://www.youtube.com/watch?v=I12tm4JzUOg
A few more images of the structure:
http://www.dezeen.com/2010/03/31/arcelormittal-orbit-by-anish-kapoor/
and a nice commentary by Dan Fox, senior editor of Frieze Magazine,
http://www.frieze.com/blog/entry/political_orbit/
Dan Fox finishes his article with:
Kapoor can waffle all he likes about how the tower demonstrates his and Balmond’s interest in ‘the way that form and geometry give rise to structure’, but the bottom line is that the ArcelorMittal Orbit is a monument to politics and big business, and as critic Owen Hatherley observes, this kind of “‘aspirational’, ‘iconic’ but deliberately meaningless, non-figurative edifice” fits their purposes perfectly. File under ‘art and power’.