Work experience is the best way to realise, I wanted to be a journalist until i went to report in the courts on work experience.
Law books are an idea, but I am thouroughly interested in law and find a fair majority tedious.
However if helping people is your aim, you have to remember in law you can only help people where possible, theres normally only one 'winner'.
The times section is good, as is their website, but I have to say work experience is the best way.