Please feel free to add to this list or start a discussion about your own experience in SL.

MIT Second Life wiki: https://wikis.mit.edu/confluence/display/SL/Second+LIfe+at+MIT+Home

(contains useful links etc)

IBM Second Life collaboration page: http://www-304.ibm.com/jct09002c/isv/marketing/industrynetworks/benefits/second_life.html 

Second Life Science: http://theforcethat.blogspot.com/2007/02/virtual-science-in-second-life.html

(see bottom for links to the Second Life International Science Museum) 

Second Life Portugal: http://www.slportugal.com/