Steve,

No it is not difficult, just time consuming. I replaced mine about two months ago. To access the bulb you have to first remove the ashtray (two screws), the coin tray (two screws) and the centre arm rest (lift front inside flap to access two screws). The screws are of the torx type, found elsewhere with the car including the engine compartment,(can't remember the size). Also the black dress plate behind the handbrake pops off as well. After doing all of the above the centre column lifts up and you can access the bulb. A great manual to have is the "Lighting, instruments and other electrical componants" for the 850 published by Volvo literature. In it details the replacement and as well as other great information....BTW the job takes about 45mins...