Infrared wireless LANs, which are intended for indoor use, are limited to operation over relatively short distances (a paper from IBM, for example, describes operation in a 30-by-30-foot room).
Radio-based IEEE 802.11 LANs work over longer ranges and are capable of outdoor operation. The distance you'll get depends on the data rate that you run (slower rates go farther) and what's in the way of the signals, such as walls or trees and shrubbery. In general, you can expect ranges of 5001,400 feet. Some manufacturers offer "range extender" products for longer range requirements.