Increase iPhone/iPad Volume By 20% Using Volume Booster 4.0

Volume Booster, the famous tweak that can increase the default volume of the iPhone and iPod Touch by about 20%, has recently been updated and became compatible with iOS 4, iPhone 4 and iPad.

Installation is very simple, just download it through Cydia and then activate it through Winterboard, if it does not already installed, it will download automatically with the application.
You can find VolumeBooster 4.0 for free on Cydia through the repository of ModMyi.