Read original post by Hari Pulapaka at Windows 8 App Developer Blog
In my previous post (Being productive in the background), I explained the Windows 8 background model and how your app can be productive even when it’s not on screen in a power efficient manner. In today’s post, I will talk about background tasks and how your app can run code in the background even when it is suspended. I will describe two common scenarios with example code that show you how to run your own app code in the background; downloading POP email every 15 minutes with a lock screen capable app and how any app can do work in the background when the device is on AC power.