I have a list of font names in my app, which are all displayed in the font they represent. The following three do not work though:
ArialRoundedMTBold
ChalkboardS
I had a similar issue with not finding Chalkduster - even though IB listed it as a font and it's listed as an IOS font. I discovered that the list of fonts on iPhone and iPad is not identical.
Chalkduster is available for iPad but not iPhone. Chalkboard is available on iPad 4.x but not 3.x. It is available on iPhone 3.x & 4.x.
More details here: http://www.whatsyourdigitaliq.com/2011/05/11/fonts-available-in-various-versions-of-ios/