Commit to wrong branch. How to fix?

I commited to the wrong branch and I can't figure out what to do. To  
make matters worse I then did 'git reset HEAD^' which has made things  
much worse. It didn't remove the commit and now I can't change  
branches. I'm utterly confused. Any help much appreciated!

Moral - use git status liberally and read it carefully before doing  
anything. A 'git undo" command would be great is someone is feeling  
generous :-)