If you spend too much time with your iPhone/iPod Touch, chances are that sooner or later you will get bored off with the theme, looks or UI of your phone. If you have got bored with the default font on you iPhone, then Font Swap can do the magic for you.
Font Swap is an app which can change and give new look to the fonts on your iPhone. This app works on Jailbroken iPhones and is installed via Cydia.
FontSwap enables you to change your System, Lock and Notes Font using the currently installed fonts on your iPhone.
For details on how to get this app and all other details, watch this video on Youtube.