This article is from the Running FAQ, by Ozzie Gontang with numerous contributions by others.
Start with back issues of _Runner's World_, _Running Times_, etc. They
usually have articles on treadmills as winter approaches. The December,
1993 _Runner's World_ contains a list of manufacturers, a chart to convert
between treadmill running at various inclines and outdoor running, and some
sample workouts. The January, 1996 _Runner's World_ contains brief
evaluations of many different treadmills (mainly high-end models).