Submitting code to OpenSim
From OpenSimulator
Code is submitted to OpenSim via patches attached to our Mantis bug tracker. One way to generate these is by using the Subversion command line
svn diff > my.patch
from the root OpenSim directory. This will package up all your changes into a nice easily appliable file. I also hear that this can be done graphically via TortoiseSVN on Windows.