Can I change the font style on Iphone 4?

Can I change the font style on an Iphone 4? If so, how? Thanks

Added (1). How do I jailbreak it?

Yeppy… Only AFTER you Jailbreak it!
otherwise, no.
you have to use only Apple created fonts.

Nope.

Jailbreaking depends on what version of iOS you are running.

Jailbreaking changes the iOS (SOFTWARE) its really cool there are so many things that you can change, keyboard colors, apps, the way apps move, pictures, were it had your carrier you can change it to anything, really you can do anything, you can prob recreate the iOS. Check the safe and easy jailbreak guide:

http://iphonejailbreak-unlock.com/how-to-unlock-jailbreak