How can I change my background on my iPod 3rd generation?

Certainly! You go into Settings (the icon with 3 gears) then to something such as 'Brightness and Wallpaper' from which you can change both the wallpaper for the lockscreen, and the wallpaper for the background behind your apps. 🙂

From the Users Guide for 4.3.3:

Adding Wallpaper

You can set an image or photo as wallpaper for the Lock screen. You can also set

wallpaper for your Home screen. You can choose an image that came with iPod touch,

or a photo synced to iPod touch from your computer.

Set wallpaper (iPod touch 3rd generation or later):

1 In Settings, choose Wallpaper, tap the image of the Lock and Home screens, then tap

Wallpaper or an album.

2 Tap to choose an image or photo. If you choose a photo, drag to position it and pinch

to zoom in or out, until it looks the way you want.

3 Tap Set, then choose whether you want to use the photo as wallpaper for your Lock

Screen, Home screen, or both.

What iOS do you have and what model iPod? If it s 8 or 16 GB capacity, it is a 2G iPod and you can only change the lock-screen background. Also see:

Identifying iPod models

You have 2G ipod. Apple only made 32 and 64 GB 3G iPods. When the 3G iPod was introduced, the 8GB 2G continued to be sold with updated iOS. Sorry.

Not if your sister has a 2G ipod. You can only change the lock-screen background on the 2G.