If the radio has two holes either side you can get it out with a pair of standard release keys sold at Halfords and many other car shops. If there are no holes you need to push in a piece of flat metal with a notch in it into each side of the radio to grip onto the two silver release clips which sit just behind the facia of the radio. The Haynes manual shows a picture with dimensions of Peugeot's own release keys. I made a pair by cutting a metal rule in two and cutting a notch in each end. The majority of the time you just end up resorting to brute force to pull these radios out of the dash as they have a nasty habit of becoming stuck.
Tommy, March 2005