Pay Phones Everywhere...

It seems like every corner I turn, there is another pay phone in New York City. I find this quite curious being that it is 2007, and even homeless people have cell phones. After living in Chicago for the past eight years, I have (or thought I had) come to the understanding that pay phones were a relic from the 20th century, and that there were occasionally a few to be seen (such as "L" platforms in Chicago) they were pretty much gone. I cannot think of a single free-standing pay phone in the Chicago Loop (let me know if you know of any). I never see anybody using them, as all the drug dealers have Blackberries, so I ask.... Why are there pay phones everywhere?