You can place an add and sell something for bitcoin with your smartphone.
You can apply on some job using smartphone and ask them to pay you in Bitcoins.
Smartphone is super super godo device. It helps you to connect to the internet and communicate with whole world. Oh and you can keep a bitcoin wallet on your smartphone where you can store Bitcoins you will gather on your ventures.
Oh. Why you posted this question in Alternative currencies and under Speculations section of forum? Quite wrong place. If you place it on right section you will get way more accurate answers.