Magic Themes - With Magic Themes, your old Sony Ericsson P800 will look like a new P900, because now you can use P900 themes (UTZ files) right on the device! This sounds unbelievable, but it is.
Magic Themes is a useful utility that allows you to change almost everything on your smartphone
VITO ThemeEditor - FREE for non-commercial use PC-based application that allows you to create your own themes for using on the P900. Start with basic settings, such as defining a default color scheme, then set backgrounds for every screen element, and finish your masterpiece with creating advanced masks and image patterns. Every setting is optional, and you can skip any step