This question relates to iOS pre-3.2. As of 3.2 this functionality is easily achievable using samvermette's answer below, and I have changed the Accepted Answer (from commanda to samvermette) to reflect this. I can't give credit to both answers (besides upvotes) but they are both good.
I would like to have an app include a custom font for rendering text, load it, and then use it with standard
UIFont* font = [UIFont fontWithName:@"Harrowprint" size:20];
iOS 3.2 and later support this. Straight from the What's New in iPhone OS 3.2 doc:
Custom Font Support
Applications that want to use custom fonts can now include those fonts in their application bundle and register those fonts with the system by including the UIAppFonts key in their Info.plist file. The value of this key is an array of strings identifying the font files in the application’s bundle. When the system sees the key, it loads the specified fonts and makes them available to the application.
Once the fonts have been set in the
Info.plist, you can use your custom fonts as any other font in IB or programatically.
There is an ongoing thread on Apple Developer Forums:
https://devforums.apple.com/thread/37824 (login required)
And here's an excellent and simple 3 steps tutorial on how to achieve this (broken link removed)
[UIFont fontWithName:@"CustomFontName" size:12]to get the custom font to use with your UILabels and UITextViews, etc…
Also: Make sure the fonts are in your Copy Bundle Resources.