There are 2 crews working:

One filming with Simon in Fremont, Las Vegas. The other filmed yesterday (Monday) at a Church, Motel & Warehouse in Glendale/Burbank.

 

Filming today (Tuesday) at Belasco, a downtown Los Angeles nightclub https://twitter.com/#!/goforlocation/status/192348407178870784/photo/1

 

Update1: On Wednesday, filming in the North Los Angeles County (desert) area of Palmdale/Lancaster http://twitpic.com/9b33jd

 

Update2: Filming the rest of the week at a home in Palmdale-N L.A.County (playing as Las Vegas) https://twitter.com/#!/goforlocation/status/192576118367322112/photo/1