Subversion clients can now write to GitHub

Yes. The use case is for organizations who have a lot of developers, some of whom want to (or demand to) continue using Subversion for their VCS needs. This can include people who don't really want to use VCS at all, but have become comfortable with some tool like TortoiseSVN or the like. We would obviously prefer everyone use Git, but we want to provide a bridge to help teams get there.

Also, you still have correct and clean merges, but since it's somewhat difficult for me to figure out what your last base version was when an svn client commits, it uses the latest version number of any submitted file as one parent and the current head as the other for anything that needs to merge, so the history may have more parents in it than are strictly necessary. If the merge does not happen cleanly, the server will reject the merge and you have to update and fix locally, like normal SVN. However, since the concept is new, I wanted to leave as much information in the Git history as possible, thus the extra parentage information.

Or you could just use this: http://hg-git.github.com

Not quite the same, I know, but the best thing if you want to use a combination of hg and github.

Both sites have APIs, it could be done though a third-party. I've thought about giving it a shot a couple times, but I have more important things on my plate.