Willow Garage will be running a full day tutorial session on May 7th at ICRA 2010.
You don't have to wait until May since there are a series of tutorials already available online. The first few might seem a bit tedious and boring but the reasoning will become clear as you get to later tutorials (or will already be clear if you have used Player/Stage). You only need a computer to run the basic tutorials and get an idea as to how useful ROS could be for your robot, so get started and don't wait for your PR2 to show up.
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