As for observing classes, I was very impressed with the observations that I did while undertaking a teacher training course for language educators in Second Life, run by http://www.languagelab.com. They are a serious language school, with a sizable city in Second Life, employing highly trained teachers and teacher trainers and material designers and are doing the most when it comes to really using Second Life well for language teaching. I suggest contacting them - they may not be running another teacher training course for a while, but you could always sign up to take Spanish or Italian and get to observe teachers in action
Avatar Languages is another language school that is also active, but the classes are one-to-one: http://www.avatarlanguages.com - check out their blog for ideas of how you can teach ESL without having land in SL.
Second Life English is another group worth contacting: http://www.secondlifeenglish.com (although I'm not sure how active they'll be during the summer) - the people involved in this, and the English Village island in Second Life were the first people to offer ESL in Second Life and have therefore a lot of experience. They have gone through the usual stages that anyone does when starting to teach ESL in Second Life (i.e. trying to teach in a classroom environment, with a board is usually the first one that goes out the window - it's still surprises me that anyone wants to duplicate this in a world where you can teleport and fly and build or find any scenario you want, but they do - it shows a complete lack of experience with the environment and/or a lack of reflection on what is needed for language learning to take place)
There are others, but most of them do not offer any innovative practice and show signs of trying to jump on the bandwagon without doing any legwork.
Speaking of legwork, if you've just joined it may be worthwhile getting in touch with a more active group of educators. A group of Webheads meet every week to discuss Second Life education and create lesson plans (most are English language educators too). Find out more here: http://slexperiments.pbwiki.com
Finally, if you'd like a good overview of the state of the art re. language education in Second Life, I recommend checking out the archive of the annual SLanguages conference: http://www.slanguages.net/archive.php which was held on the Edunation island (a great place to set as your home base if you want to meet other educators - you'll always find people there you can talk to)
Hope this helps - please feel free to get in touch. I am not directly involved in ESL TEACHING in SL (I spend most of my time working on the British Council's SELF-ACCESS centre for 13-17 year-old language learners in Teen Second Life: http://secondlife4teens.wikispaces.com), but I have been involved in language education in Second Life since 2006 - my avatar name is Baldric Commons