The default fonts of the Android OS are pretty much good and they are easy to read but if you are using your Android phone for a long time and are bored with the default fonts then you can change the default fonts and give a new look to your phone.
Users of Android 2.2 have a built-in option to change the default phones but there are not any new fonts provided. You have to download some fonts from Android market and then install them on your phone. Installing fonts is as easy as you take screenshots on Android phone. Here is a quick guide on how to change the fonts on android phones.