http://developer.apple.com/iphone/program/

http://developers.facebook.com/

Definitely there have been quite some individuals get serious on one or the other.

App Store provide interesting platform for individuals to develop their own application and make tiny or big money based on the popularity and willingness of users to pay. This definitely attracts open source gurus, colleges kids to play with it.

There have been quite some individuals to write facebook applications. Some companies do that as well. Zynga(http://www.zynga.com/) claims to be the largest social gaming network and it have tons of games as facebook application.