Apple currently publishes two notes listing the fonts provided with its products:
For OS X 10.8, HT5379
For iOS 6, HT5484
Regarding conditions on their use, the OS X License reads as follows:
E. Fonts. Subject to the terms and conditions of this License, you may use the fonts included with the Apple Software to display and print content while running the Apple Software; however, you may only embed fonts in content if that is permitted by the embedding restrictions accompanying the font in question. These embedding restrictions can be found in the Font Book/Preview/Show Font Info panel.
For OS X 10.8, HT5379
For iOS 6, HT5484
Regarding conditions on their use, the OS X License reads as follows:
E. Fonts. Subject to the terms and conditions of this License, you may use the fonts included with the Apple Software to display and print content while running the Apple Software; however, you may only embed fonts in content if that is permitted by the embedding restrictions accompanying the font in question. These embedding restrictions can be found in the Font Book/Preview/Show Font Info panel.