Volvo S60 R Forum : “My Volvo won't shift out of park. I have the ignition on and am pressing on the...”

Sounds like there may be a problem with the linkage or the electronics inside the transmission.  You will have to have this taken to a mechanic and diagnosed.

I had this problem once.  There is a micro swith that interlocks the brake with the shifter.  

I wrote a post about it here:
http://knol.google.com/k/john-robb/taking-volvo-out-of-park/3ou0v29v7gexj/2#

I just had this same problem fixed a couple of weeks ago.
The calibration for the shifter was off. So the car didn't think it was in park.
Therefore it wouldn't release the key, and then my battery went dead.
Total parts and labor was $274.00