The latest issue of the Journal of Medical Internet Research has an article on Second Life and its uses in a health context. The Canadian researchers surveyed 68 health presences in Second Life and came to the following conclusion:

We found a wide range of health-related activities on Second Life, and a diverse group of users, including organizations, groups, and individuals. For many users, Second Life activities are a part of their Web 2.0 communication strategy. The most common type of health-related site in our sample (n = 68) were those whose principle aim was patient education or to increase awareness about health issues. The second most common type of site were support sites, followed by training sites, and marketing sites. Finally, a few sites were purpose-built to conduct research in SL or to recruit participants for real-life research.

You can read the full article here. There’s also an appendix listing the 68 sites.