I cannot download the Facebook app on my itouch?

[kmu]

You need to upgrade your software to IOS 5 before you get started to use Apple App Store ....
In order to u need to follow some instructions.. i did that by using I-Tunes from my computer....
Please follow these steps to fix it....

Use this link http ://support .apple.com/kb/TA38529
Or
Follow those instructions

For Windows users

Insert the CD that came with your iPod into your computer.

Open My Computer, then double-click the iPod CD to start the installation.

In the resulting dialog, choose your preferred language from the menu choices, then click OK.

The iPod for Windows Install Wizard starts up. Follow the instructions to install iPod software onto your computer, connecting your iPod to your computer (if asked) as follows:

To connect iPod, iPod nano, or iPod mini: Connect the Dock Connector side of the cable that came with your iPod to the Dock Connector on the bottom of your iPod (the rectangle with horizontal line icon should be face up). Connect the USB side of the cable to a high-powered USB port on your computer.

To connect iPod shuffle: Remove the USB cap and plug the USB connector into a high-powered USB port on your computer.

Note: High-powered USB ports are generally the ones that reside on your computer or on a powered

USB hub. If you want your iPod battery to charge while connected, avoid using the USB port on your keyboard or non-powered USB hub.

When your computer recognizes iPod, it may update software on your iPod if needed (click Update if you get a dialog that says your iPod needs to be reformatted or restored). When finished, your iPod software will be installed at the default location, C:\\Program Files\\iPod\\ (unless you choose another folder).

The installer will then install iTunes if it isn't already installed on your computer, or if you have an older version installed than the one that came on your iPod CD.

When the installation is complete, follow the instructions to restart your computer.
Once your computer is back up, you should be greeted by the iPod Setup Assistant (if your iPod is still connected). Type a name for your iPod in the top field.

Choose the "Automatically update songs on my iPod" checkbox if you want to sync your entire iTunes music library and playlists to your iPod each time you plug it in. If you want control of what goes onto your iPod, deselect this checkbox.

If you have an iPod with a color display, you can have iTunes automatically copy your photos to your iPod (using your settings in iTunes preferences) to fill any remaining space by choosing the "Automatically copy photos to my iPod" checkbox. Then choose a folder from the Synchronize photos from menu. If you prefer to copy photos manually, deselect this checkbox.

Click Next to go to the next screen. If you'd like to register your iPod at this time, click Register My iPod. Click Finish to end the setup process and open iTunes (you should see your iPod hanging out in the iTunes Source pane.