Project Based Learning - Where to Start?

As a high school physics teacher, I have wanted to use PBL for some time.  Due to the subject matter most of my students are already good at "playing school" meaning they know how to study, take lecture notes and deliver what teachers require of them.  What many of them aren't consistently good at is exercising the ability to think independently and imaginatively.  This is particularly noticeable when I give them an open ended lab question to investigate without a "cookbook" type lab procedure to follow.  I think that PBL could be useful for helping students exercise their creativity "muscles" while researching and developing a project.  Helping them recognize the physics they need along the way to answering their research question seems to me a powerful motivator for actually understanding the physics. I want them to take responsibility for their learning rather than just passively coming to class, taking notes, and expecting me to deliver content knowledge for their consumption. My quick look at the resources available at the Butler Institute web site shows there are immediately useful resources even for teachers like me who are starting from ground zero with nothing but a conviction that PBL is one step in helping students grow as independent learners.  Thanks for giving me a place to start.