I just picked up a wide-band scanner antenna from Radio Shack, and for the
first time ever I have the ability to mount it outside and up high.
Immedietely available to me is the pole that sticks out of the roof that
all of our services come in on... electrical, phone, etc. This is the
most ideal place for me to install the antenna, however I am wondering
what sort of interference I will get from the electrical lines just inches
away.

If that is not an option than I will either have to settle for a tree or
pour a slab and put up a "real" pole. Am wondering about the validity of
mounting the antenna to the utilities pole.

Mount the antenna where if it falls it CAN NOT contact the power lines.