Gamespot has been reporting on this story for a few days ago, which basically states that Wal-Mart has pulled out all of the XBox 360 kiosks that were installed to showcase the new gaming console before the holiday spending season began. Rumors have been flying as to why they pulled the kiosks, but the party line is that the 2.4GHz wireless spectrum used by the kiosks were interfering with Wal-Mart's internal wireless system, and that is a big no-no.
After the original story came out, Wal-Mart contacted GameSpot to say that the glitch only affected Wal-Mart stores using an older inventory system. So, supposedly they plan to have "kiosks in 1,200 stores by the first week of November; by mid-November, all Wal-Mart stores should have Xbox 360 kiosks."
You can read the gamespot post here.