Following is the list of the font names & family really available on an iPhone :

Family: American Typewriter
Name: AmericanTypewriter
Name: AmericanTypewriter-Bold

Family: AppleGothic
Name: AppleGothic

Family: Arial
Name: ArialMT
Name: Arial-BoldMT
Name: Arial-BoldItalicMT
Name: Arial-ItalicMT

Family: Arial Rounded MT Bold
Name: ArialRoundedMTBold

Family: Arial Unicode MS
Name: ArialUnicodeMS

Family: Courier
Name: Courier
Name: Courier-BoldOblique
Name: Courier-Oblique
Name: Courier-Bold

Family: Courier New
Name: CourierNewPS-BoldMT
Name: CourierNewPS-ItalicMT
Name: CourierNewPS-BoldItalicMT
Name: CourierNewPSMT

Family: DB LCD Temp
Name: DBLCDTempBlack

Family: Georgia
Name: Georgia-Bold
Name: Georgia
Name: Georgia-BoldItalic
Name: Georgia-Italic

Family: Helvetica
Name: Helvetica-Oblique
Name: Helvetica-BoldOblique
Name: Helvetica
Name: Helvetica-Bold

Family: Helvetica Neue
Name: HelveticaNeue
Name: HelveticaNeue-Bold

Family: Hiragino Kaku Gothic **** W3
Name: HiraKakuProN-W3

Family: Hiragino Kaku Gothic **** W6
Name: HiraKakuProN-W6

Family: Marker Felt
Name: MarkerFelt-Thin

Family: STHeiti J
Name: STHeitiJ-Medium
Name: STHeitiJ-Light

Family: STHeiti K
Name: STHeitiK-Medium
Name: STHeitiK-Light

Family: STHeiti SC
Name: STHeitiSC-Medium
Name: STHeitiSC-Light

Family: STHeiti TC
Name: STHeitiTC-Light
Name: STHeitiTC-Medium

Family: Times New Roman
Name: TimesNewRomanPSMT
Name: TimesNewRomanPS-BoldMT
Name: TimesNewRomanPS-BoldItalicMT
Name: TimesNewRomanPS-ItalicMT

Family: Trebuchet MS
Name: TrebuchetMS-Italic
Name: TrebuchetMS
Name: Trebuchet-BoldItalic
Name: TrebuchetMS-Bold

Family: Verdana
Name: Verdana-Bold
Name: Verdana-BoldItalic
Name: Verdana
Name: Verdana-Italic

Family: Zapfino
Name: Zapfino