Heat Fan Issue

I got this strange noice from the heat/coupe fan when I switch it to diffrent speeds, I can't really localize the fan motor it self.

Does nyone know how hard it is to change the fan motor in the car?
It seems all built in and really tricky to replace.
It's a really good car so I really need to fix it before winter.
Should I leave this job to a mechanic?

The car is a Volvo 245 1993 Classic.

Check out http://brickboard.com/
This site has tons of info and give you good advice on repairs etc.