None of the phones that Cingular offers list GPS as a capability,
because Cingular is not depending on a GPS or assisted-GPS solution for
Enhanced 911 services.  Instead, Cingular intends to use a system that
relies on triangulation (determining signal strength and time delay in
the signal among multiple cell sites to find the user's location).  The
advantage to this approach is that an end user does not need to upgrade
their phone for location services to work.  The drawback is that
Cingular has had some difficulty getting their system to work in some
areas, particular in places where cell sites are spread out farther than
usual and along places where only major highways are covered (because
the cell sites are strung out along a line, making triangulation hard to
do).

As far as progress goes, Cingular has deployed Enchanced 911 in a number
of areas, but they're not yet at 100% coverage.  All of the carriers are
required to provide quarterly updates to the FCC on their progress, and
you can find these updates at:

http://www.fcc.gov/911/enchanced/reports/