with the ignition off , press and hold the odometer reset button.
turn on the ignition whilst still holding the button in.
watch the display count down from 10 to 1.
thats it no more spanner.
Paul, October 2008
It means your car is due a service, it can be reset if service has been done recently.
eveningstar ex peugeot, September 2008
It's the Service Indicator.
See http://www.peugeot206cc.co.uk/downloads/handbook.pdf