A friend of mine has a macbook air and an android phone but no internet access except for the phone. I had an old airport extreme lying around so I thought I'd see what I could do with a local wireless network. All her music is on an external drive that is plugged into the MacBook air. So I set up the Airport Extreme created a local wi fi and plugged the external drive into the Extreme so that the drive is now showing up as a network device. Now the MacBook can see the external drive and can play music over the wifi plus the drive is searchable. OK so that's pretty good so far. But now what I'd like to be able to do is somehow use the phone's data to plug into the wifi so that the MacBook can use it, but I can't work out how to do this.