An apropos link from daringfireball today:
http://www.jordanm.co.uk/tinytype
lists the available 'system fonts' on iOS/Android/Windows Phone/Blackberry.
For communication purposes, it would be great to fork it (
https://github.com/jordanmoore/tinytype) and add the available default
system fonts on Mac OS, Window 7/8, Ubuntu, Red Hat, etc.
(Then the only missing piece would be the font-mapping information, so you
could tell what font the string "serif" or "Helvetica" (say) is mapped
to
on the various platforms.)
--scott