How do you get wallpaper on the iphone?

You’ll have to jailbreak your phone using Pwnage Tool, which installs Cydia. In Cydia there’s an app called WinterBoard.

From there you can install different themes in Cydia that work with Winterboard, or you could SSH via SFTP your own wallpapers. If that was foreign sounding to you, might want to stick with the pre-packaged themes in Cydia.

If you’re simply talking wallpaper, here’s what I did: create an album in iPhoto and sync it with your iPhone. From the phone browse to the picture you want and set it as the wallpaper (from the button in the lower left corner). That should do it!
That’s also assuming you’re using a mac. As far as windows goes I’m not sure how photo syncing works. Hope this helps!

Simply browse to a picture you like on the web with your iPhone. Touch it and hold down, save it to your iPhone. Now you can set it as background/wallpaper using the settings menu or from the button in the lower left corner (thetmie) when viewing your photo’s.