OKC trunked radio
It's definitely true that OKC will go Ericsson trunked. You can find more information at the City of OKC's website under public safety.
Near OKC, Edmond, Norman, and Shawnee have trunked systems. Cleveland County SO has a few talkgroups on the OK Smartzone repeater in Norman.
You may want to visit Matt Englebrecht's Yahoo! Group (
http://groups.yahoo.com ) and see the resources available for OKC trunked scanning. Unfortunately, I forget the exact name of the group, but a search at the above URL will give the link.
It's important to obtain a copy of the TGs that interest you, so you can lock out agencies in which you have no interest (e.g., sewer plant, city admin., etc.)