I'm also concerned about this weekend. A lot of people are going to be in Phoenix.
On another thread I mentioned the symbolism. Phoenix has a team called the SUNs, and the SUN was the first anthrax target. President Bush was rumored to throw out the first pitch (the SON of Saddam's enemy no. 1). Muslims praying in the U.S. would face east, towards Mecca, and towards the sunrise.
Of course, the terrorists had no way of knowing that the Diamondbacks would make it to the World Series this year. They could have just lucked out, and happened to pick Phoenix, not knowing there would be a 40000+ concentration of potential casualties (fans) packed close together.