Follow the link called "passenger dash access" including removing the kick panel, knee bolster and glovebox on volvospeed.com (Bay13). The knee bolster in my car fit very tight and after removing it I enlarged slightly the 3 mounting holes so it could be easier to put back. The various connectors on the blower housing clip on and you will see how to release the clip and pull each one off (usually no need to disconnect). After that you just remove the screws holding blower motor to housing.

Before replacing the motor (unless it really burned up) it might be worth checking if its connections are poor or dirty - also you can pull the motor out of the plastic housing and see if the brushes and commutator have gotten dirty or corroded. I have got almost 2 years of additional life from my original motor by cleaning everything thoroughly. Eventually it will go, I know, but not so far.