This talk, by Professor Aletta Bonn from the end of March, provides an overview of what is needed to make citizen science more effective. While the research was done in Germany, many of her discussion points are relevant in other places.
Especially interesting are the Q&A at the end (around 25 min) which demonstrate the issue of trying to pigeon-hole citizen science into a specific thing – participation, education. Interesting is also the acceptance of Wikipedia as a source of valid knowledge.
There are other talks on Science 2.0 from this conference at http://www.science20-conference.eu/programme/