Some reviews and meta-reviews of the research literature into the use of games (mostly) and virtual worlds in teaching and learning. Reviews indicated as (short) are typically a standard research paper which looks at a wide range of literature, rather than a full-on review.
You might also want to find any relevant PhD thesis, as a common approach is to conduct a literature review which forms the first few chapters of the published work.
2009: (Short) Literature review on the use of video games in humanities education. [Slideshare] By Max Lieberman.
2009: (Short) Best Practices for Integrating Game-Based Learning into Online Teaching. [HTML] By Rudy McDaniel. Published by the Journal of Online Teaching and Learning.
2009: Can Video Games Promote Intergenerational Play & Literacy Learning? [PDF] By Cynthia Chiong. Published by The Joan Ganz Cooney Center.
2009: Virtual worlds — past, present, and future: New directions in social computing. [PDF] By Messinger et al. Published in Decision Support Systems.
2008: Current practices in serious game research: A review from a learning outcomes perspective outcomes perspective. [PDF] By Wouters et al.
2008: Games in Schools literature review. [PDF] By Maja and Paul Pivec. Published by the European Gateway to Science Education.
2008: Once Upon a Game: Rediscovering the Roots of Games in Education. [PDF] By Luca Botturi and Christian Sebastian Loh.
2007: (Short) Narrative and Social Collaboration in the integration of Games in the Curriculum. [PDF] By Heather Conboy and Chris Goldsmith. Published by the Education in a Changing Environment conference.
2006: Learning Patterns for the design and deployment of Mathematical Games: Literature review. [PDF] By Mark Childs et al. Published by the TeLearn Open Archive.
2006: Learning in Immersive Worlds. [PDF] By Sara de Freitas. Published by JISC.
2006: (Short) How can exploratory learning with games and simulations within the curriculum be most effectively evaluated? [PDF] By Sara de Freitas and Martin Oliver. Published in Computers and Education 46 (3) 249-264.
2005: (Short) Classiﬁcation of learning outcomes: evidence from the computer games literature. [PDF] By Harold F. O’Neil, Richard Wainess, and Eva L. Baker.
2005: The effectiveness of instructional games: A literature review and discussion. [PDF] By Robert T. Hays. Published by the US Defense Technical Information Center.
2004: Literature Review in Games and Learning. [PDF]. By John Kirriemuir and Angela McFarlane. Published by FutureLab.
2004: The use of computer and video games for learning: A review of the literature. [PDF] By Alice Mitchell, Carol Savill-Smith. Published by the Learning and Skills Development Agency.