How does this change as of June 18, 2013 affect my existing repository with a file that exceeds that limit? I last pushed 2 months ago with a large file.
I tried a couple of the above answers with no luck. But eventually I found a solution using Github Desktop. Click 'Repository', 'Undo most recent commit'. It allowed me to do it twice, just enough to remove the offending commit. (I had already deleted the large files from the repository).