Norbert and I have a new review out that discusses cell-based and in vivo RNAi in various species and emphasizes interaction of the RNAi screening field with other fields of study.
Mohr & Perrimon (2011) RNAi screening: new approaches, understandings, and organisms. Wiley Interdiscip Rev RNA. doi: 10.1002/wrna. PubMed ID: 21953743