An interesting article about the Nike ad:
http://www.pluginz.com/news/1777
And the full 90-second ad as hosted by the production company:
http://www.darnellworks.com/a52/media/magnet90.mov
It's not at all surprising, but it did remove some of the magic to learn that they used a double in the location shots, replacing his head and shoulders with Armstrong's as necessary.