Users who do not have broadband access at home, work or school can download Lion at Apple retail stores and later this August, Lion will be made available on a USB thumb drive through the Apple Store® (www.apple.com) for $69 (US).

In Apple's press release for OS X Lion, the company revealed that they will be selling OS X Lion on USB Flash Drive as well starting in August:

This should allay concerns about those who can't easily download Lion using their home internet connection, or may want some sort of physical media.