The Oklahoma Senate is indeed tied right now with the Republicans in defacto control (kinda like the US Senate tied with the Democrats in defacto control). I give it a 50-50 shot of going either way. Personally, I hope it tilts left just a bit, but it could go either way.
Aren't the Democrats in control in Oklahoma? Split Senate with a Dem Lt. Governor.
Actually, it looks like they're in equal control with maybe the Democrats a bit ahead with Lt Governor Jari Askins.
Here is a link to the leadership page --
http://www.oksenate.gov/Senators/leadership.htm