While finishing this Spring semester courses, one of the main media industries we focused on was the game industry. In the context of Jenkins' convergence culture, one of the students looked explicitly at the consequences of the consumer as co-creator for the professional identity of gamemakers.
The game industry has cleverly used gamers as 'modders' (creating modifications of existing games using increasingly sophisticated SDKs: Software Development Kits). David Nieborg and Jose Pedro Tavares, Rui Gil & Licinio Roque are among those who signaled an emerging mod culture, where the player is (also) author, and the notion of collective authorship potentially undermining the (sense or extent of) creative control of the professional game developer.
Several people have written eloquent books on the issue of collaborative media production, some of which works can be downloaded or read for free online (see Yochai Benkler's "Wealth of Networks", Eric von Hippel's "Democratizing Innovations", Charles Leadbeater & Paul Miller's "Pro-Am Revolution", and Lawrence Lessig's "Free Culture" for example).
Others have made available their papers or essays on the topic, thus providing additional wealth of insight and information on the topic, like Henry Jenkins, Lars Bo Jeppesen, Axel Bruns, Christoph Neuberger, Ari Heinonen, and many others.
UPDATE (23.04.06, 18:29PM): All of this of course needs a critical perspective, too - not just regarding the tensions in working on one's professional identity as a game developer. One way of looking at the corporate embrace of user co-creation is to question the implied valorizing of people's voluntary creativity and cultural production. It is in this context that Tiziana Terranova wrote: "Working in the digital media industry is not as much fun as it is made out to be" (originally in Social Text 18/2, 2000). She refers to the notion of 'free labor' as the ultimate engine of the so-called knowledge society, information age and digital economy. A similar argument makes Leila Green (in a 2001 issue of M/C Journal on 'Work'), asking why we are not getting paid if all that we do (as consumers or prosumers of media) is working to be audiences for media organizations to be sold to advertisers.
UPDATE (01.05.06, 11:34AM): Another beautiful and telling quote (especially when read next to Henry Jenkins' work on convergence culture and the 'rewarding' user experiences it generates) from Terranova's essay: "In the overdeveloped countries, the end of the factory has spelled out the obsolescence of the old working class, but it has also produced generations of workers who have been repeatedly addressed as active consumers of meaningful commodities. Free labor is the moment where this knowledgeable consumption of culture is translated into productive activities that are pleasurably embraced and at the same time often shamelessly exploited."