Customizing IOS without jailbreak

Since IOS 6 jailbreak is still in development u can go to these links for non jb tweaks
http://lifehacker.com/5968627/top-10-handy-ios-tweaks-that-dont-require-jailbreaking

cydiahacks.com

For blank homscreen icons (cool)
http://iempty.tooliphone.net/en/customize/iphone/customize-your-iphone-springboard-with-transparent-icons