The Japanese virtual world Meet Me has been released.  It's the same basic idea as Second Life with some key differences that should be very beneficial for teachers of Japanese

• There are rules governing behavior.  It's not the wild west you'll find in Second Life.
• It's intended only for a Japanese audience, so you can be reasonably sure people you meet in the environment are Japanese.
  
• It's a virtual representation of Tokyo and could easily be used as an example of Japanese modern culture.

The download is free, though you do have to register with your email address.  Also, for XP you have to make a change in the Control Panel to read the Japanese characters in the environment. Go to Control Panel > Regional and Language Options > Languages > Advanced Tab >  then for the drop down list set "Select a language for non-unicode languages” to Japanese.  Thanks to Takeshi Sengiku at Gettysburg for find this.