Car will not shift out of park

Hi all - I am new to this board. In fact, I used to post over at camaroz28.com when I still had my Z28 (don’t hold that against me ), so I know these forums have some very knowledgeable people in them. The catalyst for me to register here though is I am having some trouble with my 2000 V6 Mustang.

The problem just started today, the car does not want to shift out of park. (Yes, I am pushing the brake pedal all the way in.) I will even try to turn the car off/on several times, pump the brake, etc. The steering wheel isn’t locked or anything either. It will eventually let me put it in drive, but the next time I put it back in park it wont come out again.

I am wondering what could be causing this? Has anyone had this problem before?

Thanks in advance for any suggestions you all may have.

- Chris