Old Motorola bag phone w/ Cingular?

I have a beautiful old Motorola bag phone that was originally used with
AT&T Wireless. We used this phone from 1997 to about 2000 when we
replaced it with a smaller Nokia. The Nokia did the job, but I miss the
handset size and power output of the older phone.

I found the wall charging cord today while cleaning so I decided to fire
the old beast up. Except for not having a network that will recognize
it, it seems to work great.

Are there any options for using this thing, either as a second phone on
my Cingular plan or on a prepaid plan? I'd like to leave it in the
trunk of the car of occasional use. (My wife is carrying a newer
digital Nokia on a Cingular plan.)

Thanks,
Mike