Free or Open Source ITIL Tools?

alister writes "Like a lot of people, I've completed an ITIL (what's that?) Foundation Certificate and am looking to put it into practice. Picking the right tool for an ITIL implementation makes life a lot easier, but I can't find many around. I'm wondering if there are any free or open source software that helps an ITIL implementation, or if not, recommendations on a tool for a medium-sized (40 IT staff, 1200 users) organisation. There's a lot of software out there, but most of it is designed for organisations with hundreds of IT staff... and priced accordingly."