Legal primer - free/open source software

The Software Freedom Law Foundation has produced a primer for legal issues relating to free/open source software. If you're involved, you may want to have a look here.

Disclaimers: Obviously, you want proper legal advice before you do anything risky. You may run into differences in other jurisdictions. But a good understanding of basic concepts is useful when talking to lawyers. If nothing else, it cuts down on the number of time units they'll be charging you for.