Vint Falken's Free Valentine Eyes:
Free opensim content: You can find free mesh,Trees,Avatar stuff,Buidings and full sims
Opensim Archives - OAR Files
What Are OAR Files?
OAR stands for OpenSimulator ARchive. With them, you can make a full backup of your region(s), and restore them. Of course, you can also share them, so that other people can enjoy your work on their own servers and/or grid. For more information on how to use OAR files, please read OpenSim Archives.
OpenVCE 3D Assets OAR
The OpenVCE.net virtual worlds assets described at http://openvce.net/vwassets provided by Clever Zebra and the OpenVCE.net team at AIAI in the University of Edinburgh are available as an OAR (Opensim Archive) file at http://openvce.net/downloads/
Get the file "opensim-openvce.oar" from there (right click on the file in the above directory in your browser, and select download is the easiest way to obtain the materials).
A "full" set of the buildings with a large 400 seat amphitheatre intended to be placed on the corner of 4 sims is also available via "opensim-openvce-full.oar".
KatiJack Studio OpenSimulator Archive Files
A free collection of original OAR files of empty terraformed islands ready to build on: http://katijackstudio.com/