Many people jailbreak in order to change how their iPhone looks and feels. This is where you will need Winterboard. Winterboard is a free app and it can be found in Cydia. Winteboard is needed if you want to customize your wallpapers and themes. When you decide to install a specific theme, all parts of the theme will be in the Winterboard. In some themes you will be able to use only the complete theme but in others you will be able to choose elements of various themes (sounds from one theme, visual effects from other). If you seriously want to play with the appearance of your iPhone you should explore Winterboard carefully. Winterboard is immensely powerful tool for customizing your iPhones springboard.