Microsoft now offers the Windows mobile phone Custom Theme Creator. This lets you customize & create new themes for your Windows mobile phone, easily.
Because people’s phones often match their personality and unique needs, this creator has been introduced. People can create personalized themes for their Windows phone by choosing the color and design that suits their style.
Currently the Theme Creator works with only Windows Mobile 6.5 Touch Screen phones.
You can also get free themes, wallpapers & ring-tones and other goodies at Microsoft.
Check it out at windowsphone.com/theme.