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
"SLURL" (link to a specific Second Life location) for the MIT Coffee Shop: http://slurl.com/secondlife/MIT%20/111/41/24/?title=MIT%20Coffee%20Shop
The New Media Consortium is one of the main advocates of educational/research applications of Second Life. Here they provide a good introductory video to give you a glimpse of a SL workshop they held on the topic of creativity. http://sl.nmc.org/2007/12/16/oldie-but-goodie-video/
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/
Irving Wladawsky-Berger's Blog on virtual collaboration and spaces: http://irvingwb.com/
[Irving is the former head of research at IBM, and now a visiting professor at MIT Engineering Systems Division]
New York Times columnist Andy Rivkin on lecturing in real life and SL simultaneously: http://dotearth.blogs.nytimes.com/2008/03/13/second-life-and-real-life/index.html
Financial Times on the value of leadership training in SL, using the MIT Sloan Leadership Model: http://www.ft.com/cms/s/0/2f81e8e4-e8c4-11dc-913a-0000779fd2ac.html?nclick_check=1
For people with older/slower computers, the Dazzle Second Life viewer may allow you to use SL effectively: http://wiki.secondlife.com/wiki/Dazzle
US academic conference on Web 2.0 debates value of blogs and SL for higher education collaboration and research: http://www.insidehighered.com/news/2008/05/09/blogs