An easy-to-use tool created by Matthew Cazalet (sl-name) a french scripter that allow you to upload builds from sl to Opensim, and from Opensim to sl. Yes, you have really understand, change are gonna come!
Everything is explained on his web-site.
For now you can upload sl builds from your own (full perms) into opensims (standalone mode or gridmode) using an inworld script and a little software converting primitives params into xml-files.
You loose all the textures (including sculpties), but it really worth it.
In the same time, using a .txt and .xml converter, the SLOP software allows you to choose from all the builds in your opensim a special one and uploading it in the linden grid.
The inworld tool is 5000l$, but it's cheaper for such a revolution. From now, our worlds will became more and more rich.
Waiting for the Big Opening!
Feel free to ask me if you have questions about that
Julius