My current deal with Luke is that I can post whatever I do elsewhere as long as it isn't crap or offensive, I don't bill him for any time or costs involved (which can be quite substantial), I don't post anything that might be private or sensitive (eg. I gave only sanitized scores for the remote researcher application experiment, stripped of any possible identifying information), and as long as I'm not specifically told not to. This covers most of my work, and I'm happy with it.

I'm not actually sure what the legalities would be. Hopefully the copyright remains with me, otherwise I may be committing infringement when I do something like submit an article to Wikipedia...