Windows 8 developer preview has been released for public, any one can download and do a fresh install of windows 8 as it is right now not supported for virtual machines. The most important thing about windows 8 is the start screen which appears when you press Windows key as shown in the image below.
Just in case you would like to access the settings or configuration option of any app running on windows 8 start screen, you should press windows key + z to open options. Now if you want to remove, delete an app from windows 8 start screen, right click on the app icon to select it as shown in the image below.
Then click advanced text to show more options like running the app as administrator or unpin the app from taskbar as shown in the image below.
Or to simply remove the app icon from windows 8 start screen press unpin as shown in the image below.