Leandra Lederman (Indiana) has published EBay’s Second Life: When Should Virtual Earnings Bear Real Taxes?, 118 Yale L.J. Pocket Part 136 (2009).  Here is the abstract:

Millions of people participate in virtual worlds—immersive online forums such as Second Life and World of Warcraft (WoW). While some online activities lack significant economic implications, one of the attractions of Second Life, which is designed to be a commercial platform, is the prospect of making “real money.” This essay argues that profits received in the form of Lindens (Second Life’s currency) should be taxed in much the same way profits received via PayPal, a widely used electronic-payment system, are. Although Second Life profits could instead be taxed once the taxpayer sells for real money (“cashes out”), that would create a special exception for Second Life that does not exist for platforms such as eBay. It would facilitate abuse and distort economic activity.