What are Themes ?
Themes are pretty much anything that makes your iPhone look visually different from the stock iPhone look. Themes can include custom app icons, wallpaper, sounds, etc. They can vary from elementary to extremely robust.
It can turn your stock iOS in to something like this :
How Do I Get Themes ?
You must jailbreak your iDevice (iPhone,iPad and iPod Touch) in order to download and use themes.To learn more about Jailbreak,Click Here
After Jailbreak,Go to Cydia and download Winterboard.You can find tons of themes in Cydia.Go ahead and pick one,Download it and use Winterboard to activate that theme.
Whats My Role ?
Well,I create themes and upload to Cydia for you to download.