1. First, of course, you have to jailbreak your iPhone and install with Cydia

2. Next, fire up Cydia and search for WinterBoard.
3. Install WinterBoard.
4. Launch WinterBoard. Tap to tick the installed theme.
5. Click "Home" button and WinterBoard will load up the theme
Introduction to WinterBoard.
Once you have installed WinterBoard (I'll cover this in the next section), and launch it, you will see you are given several options in the main menu. First let's press Saurik. This is the only theme that comes with WinterBoard by default. It will only change the background wallpaper in the SpringBoard, but it will use scripting to dissolve between two different images. When you have selected a menu item a check mark will appear next to it. To undo a selection, just press it again. Then press your Home button and WinterBoard will load your changes to apply the new theme.