Members of the AVALON team are developing a holodeck system that can easily be set up and modified by teachers. See the thread on holodecks in the AVALON Ning:
The EUROCALL/CALICO HQ contains three Horizons holodecks, each of which can be accessed by the teleporter system - start at the Welcome Pavilion:
One holodeck is next door to the Welcome Pavilion, one is on the roof of the EUROCALL building and one is on the Sky Deck. They contain a number of scenes that we have purchased off the shelf and several new scenes that have been created by Randall Sadler. Randall and I have discussed the idea of creating a selection of scenes that could be used for different teaching situations. Suggestions welcomed.
I have dabbled a bit with the Builder's Buddy, which is packaging tool that enables you to create a scene that can be boxed and rezzed anywhere you like. The boxes can be given freely by one SL resident to another. See Nergiz Kern's SLexperiment blog:
I think such tools offer exciting opportunities for language teachers. What do you think? Have you used such tools?