How can I broadcast live to Airtime with my smartphone?

While remote broadcasting from your smartphone isn't recommended due to the inconsistency of wi-fi connections, it is possible. 

Both Android and iOS have live broadcasting tools available on their marketplace. A couple examples are iCast2 and BroadcastMySelf.

Below is a tutorial on how to broadcast live on a PC using Mixxx, but you can use almost all of the same settings for these mobile apps.