A guy my wife used to work with made a decent living as a "scout" for the cell companies back in the early days. He retired and has one of those consulting companies. I can't find his site now, but I think his name was John Abbott or some variation.
Anyhow there are tons of little pitfalls to these leases and obviously, like buying a car, this is something one side does everyday while the other does only once or so. I would recommend getting advice from a pro -- there are guys with sites that have lots more experience:
Steel in the Air- About Our Company