It is a great subject area, because the learners are often very motivated, and there are ways of supporting language learning via all sorts of media, including podcasts, web, email, skype and of course SMS.
In this case they are doing grammar exercises, working both in and out of their learning center.
The CBS article has some great learner and tutor quotes:
"You're controlling it, which is so nice," said Tracey Woodburn of Athabasca University. "A lot of people have been telling me, 'Oh, I can do this when I am watching my kid's soccer practice or when I am on the bus coming to school.'"
Student Fadieh Al-Kaloti said cellphone learning works well for her.
"You learn where you are — in the bus or in the train or maybe in the plane," she said.
thanks to Andy for the link