I was surfing the web when I found a cool set of free iPhone Themes to chance the interface off your iPhone.

If u are looking for a unique interface just download this Theme pack.
The apple iphone themes set consist 25 themes.
U can upload these free themes into SummerBoard iPhone themes directory and activate it.

Check below for the How to.

How to upload custom iphone themes on Apple iphone:

Assuming you already downloaded and installed the application SummerBoard on your iphone, you can install other free iphone themes using summberboard software as below step
1. connect your iphone to your pc
2. open WINSCP in order to connect thru lan/wifi to your iphone
3. browse to the /private/var/root/Library/SummerBoard/Themes directory
4. extract the iphonethemes.rar files to a temp directory on your hd
5. browse the themes, and choose whatever you like
6. copy themes directories to your iphone /private/var/root/Library/SummerBoard/Themes directory
7. tap the SMBPrefs icon on your iphone, goto Theme, and pick your favorite theme
Download: Free iphone themes set

The zip passowrd: S3lkcer@#%$Gda