I am looking for information about the mobile phone industry. Namely,
how much money would it cost to start a mobile phone carrier on a
budget, ie. leasing tower space. Or, how much wouuld it cost for
placing the company's own towers in the desired coverage area?
Basically looking for how much it would cost to set up the
infrastructure of a mobile carrier business like sprint, verizon, or
virgin mobile. Thanks

Wallnbroad --

This is an extremely difficult question, particularly since costs of
entry rise in markets rather than fall due to marketing costs, even
while back-end infrastructure maybe be predictable (there is some
excellent historical analysis of the auto business).

For the wireless industry there are two examples that are germane. 
One, Deutsche Telecom's issues with T-Mobile and the costs of
upgrading infrastructure:

Wall Street Journal
"T-Mobile USA Could Go Up for Sale --
Costly Upgrades Are Needed" July 5, 2005
http://online.wsj.com/article/SB112040374043476283.html?emailf=yes

The other is Metricom, a wireless company that raised $100M in an
attempt to build a cellular structure but never got much beyond 3
cities.  Metricom filed for bankruptcy in 2001 but there's quite a bit
of information about building infrastructure in its pre-2001 financial
documents.

Best regards,

Omnivorous-GA