This one is a little more simple to explain.
County commissioners are individuals that are elected to administer county government, much like a city council administers a city government.
In some states (9 of them to be exact), they are not called County Commissions, they are called County Councils and in some states, but not in all counties, they have an elected position called the County Executive.
But none of this matters in Oklahoma. We have a County Commission.
Currently the 3 county commissioners in Oklahoma County are Willa Johnson for District 1 (which seems to be the largest district and includes Midwest City, Forest Park, Spencer, Choctaw, Jones, Luther and Nicoma Park), Brian Maughan for District 2 (which encompasses Bethany, parts of Midwest City and Del City, Valley Brook, parts of Oklahoma City and Harrah), and Ray Vaughn for District 3 (which includes Arcadia, Edmond, Nichols Hills, The Village, Warr Acres and parts of Oklahoma City).
For some reason I was not able to find much information regarding who is running for Oklahoma County Commissioner in 2010. Here is what I was able to find: