In computing, a patch is a small piece of software designed to update or fix problems with a computer program. This includes fixing bugs, replacing graphics and improving the usability or performance. Though meant to fix problems, badly designed patches can sometimes introduce new problems. 
The general rule for Creative Commons development is for a developer to submit one good patch before getting access to the sourceforge.net project and unrestricted access to SVN. So, please submit a great patch, we will help you with formatting it properly, and then afterwards, we will give you proper access to the development trees.
You need to use a program called diff on most computers to compare the changes from one or more files against another set of one or more files. From this, one gets diff output.
The best is to create patches against the most current development version. This is done like this inside the checked out module from SVN:
svn diff > /path/to/patchfile.patch
For an individual file:
svn diff changedfilename > /path/to/patchfile.patch
For the entire checked out module:
diff -up oldfile newfile > /path/to/patchfile.patch
patch /path/to/file /path/to/patchfile.patch