1) Plug your idevice to the computer 2) Open up itunes 3) Right click your device on the side menu and click backup This will backup all your apps to the computer. If you sync without backup, it will erase everything on your iDevice and replace it with whatever is on your computer itunes. This will also work if you have a new computer. i.e your computer died (like mine) and you you don't want to redownload all your apps.
