The Cambridge Product Management Network held a interactive session entitled 'What a Product Manager does on the first day / week / month / quarter in their new role' on 24th March, 2011 lead by me, Arthur Meadows.
The session was attended by Cambridge's finest and highly experienced Product Managers and together, we built a 'playbook' of recommended steps / milestones for new Product Managers as they start their new role.
The results are available here, Product Manager's Playbook. Consider this to be a Product Manager's personal project plan.
BIG Hint: This answers that age-old interview question: 'What will do if we hire you'. Also, this follows nicely on from my article 'How to hire a Product Manager'.