It looks like there a few working solutions for using custom true type fonts (ttf) on the iPhone, most notably Can I embed a custom font in an iPhone application? However,
I researched this throughly, and this is the best method I found:
1) Convert font file to TTF using this online tool: http://www.freefontconverter.com/
2) Add the TTF files to your project
3) Make some configurations to your info.plist file:
3.1) Edit info.plist as source code (right click on file -> open as -> source code)
3.2) Add this:
UIAppFonts font1.ttf font2.ttf ...etc...
3.3) Your info.plist should have this now:
4) Use the new fonts just like the system fonts:
[UIFont fontWithName:@"font1" size:16.0];
(Notice no ".ttf" in the font name)