Are you rooted?

 

first you must be rooted.

2nd find a font zip that you like and put on your sd card. flash like a rom

http://forum.xda-developers.com/showthread.php?t=827266

 

If you want to flash custom fonts you need to be rooted. You can then run custom built roms that remove useless sprint apps and most of the time has better battery life. I would suggest looking through the root forum for more info. If you want to moved right to rooting then follow these instructions on this link:

http://androidforums.com/evo-4g-tips-tricks/90404-tip-how-do-i-settings-android-12.html#post1835905

Some quick glancing into the root forums pulled up this great forum for instructions as well. Will give you more answers too:

http://androidforums.com/evo-4g-all-things-root/194918-rooting-dummies-extras.html#post1715227

 

Did you read this forum?

http://androidforums.com/evo-4g-all-things-root/194918-rooting-dummies-extras.html#post1715227

Rooting is the only way to get full control over customization. Lots of people do it but you must read that forum. It will answer your questions. It voids all warranties which would imply that Sprint does not want you to do it. The cool part is that you can always un-root your phone so that they would never know. You would learn that by reading that post. If you do not like to read the posts then I would suggest you do not root. If you feel you can handle the technical things that are involved with root then you will open your world up to all kinds of customizations. Then you can visit XDA Forums and get custom roms, themes, and applications. But you must read first or you will feel lost.

 

no

 

You need a rooted phone and use the font installer app. Its super easy because it already lists more than 200+ fonts. So you need not search for fonts to install.
How to Change Android Font