I'm doing some research and am trying to find case studies (think
Harvard Business School-type cases although they certainly don't need
to be from Harvard) on a couple of different markets:

1.  Ringtones - Such a case study might cover the history of the
ringtone market and/or cover such companies as Zingy, Jamster, etc.

2.  Radio market - I'm looking for a relatively recent (within the
last few years) case study of the radio industry including possible
analysis of the threat to terrestial radio of satellite radio and/or
podcasting.  Analysis of total market size and potential growth would
be helpful here.

If you are able to find case studies for either of these areas I'll
consider it a satisfactory answer.  If you find cases for both I'll
make it up to you in the tip.

Please post any proposed answer as a comment first.  Thanks!