To remove an App Store application from your device:

1) Touch and hold any application icon on the Home screen until the icons start to wiggle.
2) Tap the "x" in the corner of the application you want to delete.
3) Tap Delete to remove the application and all of its data from your iPhone or iPod touch.
4) Press the Home button to save your arrangement.

To remove an App Store application from your iTunes library:

1) Click on Applications on the left hand side of the iTunes window.
2) Locate the application and either "right-click" or "Control-click" and choose Delete from the shortcut menu.
3) Select "Remove" when asked if you want to remove the selected application from your iTunes library.
4) Select "Move to Trash" when asked if you want to move the selected application to the Trash.

To redownload the application to your iPhone, iPod touch, or computer:

1) Go to the App Store on your device or in iTunes.
2) Make sure you are signed in with the same account used for the original purchase.
3) Locate the application and click the "Buy app"(It will be free) button or tap the price on the device.
4) You will then see a dialog that says "You have already purchased this item".  Click OK to continue with the download.