I've had a few chats with media law lecturers on journalism degrees and postgraduate qualifications recently. I'm pleased to hear that a number of them recommend the book Law for Journalists by Frances Quinn.
It's a useful and acessible law reference book for new and existing journalists. I use it when I'm running media law sessions for magazine and web publishers - I think it gives good old McNae's a run for its money.
Here are a few of the media law resources I use:
British and Irish Legal Information Institute
Jack of Kent
Judiciary of England and Wales
Press Complaints Commission
Press complaints (the unofficial site)
Any others you'd like to add?