My Nikon D5000 has 11 selectable focus points but shamefully I don't know how to choose another point other than the center point.
How can I do this?
Am I misunderstanding concepts?
First you need to set the AF area mode to Single or Dynamic on your LCD display. Then you select the point using the D-pad. You can quickly return to the centre point by pressing the OK button.
The difference between Single and Dynamic is that Single keeps the focus point wherever you put it, whereas Dynamic will try and automatically keep the object originally focused on in focus by selecting other focus points automatically.
Also note that if your metering mode is set to Matrix or Center-Weighted, you are still metering the whole scene (with a center bias in CW's case), not the selected focus point. Set your metering to Spot to meter from the selected point.