The OK-Ark Skywarn site has a great list of freqs (and is a good group, I'm a member), but it doesn't extend to Okla. City at this time. It may, at a later date, but I haven't been able to find out anything definate. If it does tie in, I'm told it will be through the Edmond 443.425 MHz machine.
The comparable system used by the Norman FO is shown here:
http://www.srh.noaa.gov/oun/skywarn/
Another good list is Keith Brewster's list, located here:
http://www.caps.ou.edu/~kbrews/spotfreq/
This list is maintained through user submissions, and may have a slight lag between a change and it's submisson to the list, but Keith does a good job of updating as soon as he gets the info.
My area of concern is north of Okla. City, so much of what I have is not of use to you. Hopefully some people south of the OKC metro area will submit confirmed freqs, what I have I can't confirm so I won't post them.
You might also want to take a look at the media freqs, as all three TV stations are active in weather chasing & reporting.
Mark S.