OKC TRACON Controller described loss of separation event when the clearance issued and/or data tag information was not accurate and a confliction developed immediately after departure.

Narrative

As a NE/SE RADAR Controller I was responsible for southeast; east; and northeast bound departures off OKC. I noticed Air Carrier X 'tag up' off the departure end of Runway 17L. At the same time I noticed Aircraft Y 1 mile off the departure end of Runway 17R turning east bound. Aircraft Y had a 'W' in his scratch pad indicating they should be turning to a 260 heading. The RADAR targets merged 1 mile south of Runway 17L at 3;000 FT MSL just as Air Carrier X called initially on frequency. I immediately issued traffic as 'off your right' as the targets were so close I couldn't give an accurate 'o'clock' position. Air Carrier X reported the traffic in sight I issued a climb clearance to 15;000 FT and turn east bound. Air Carrier X later asked if they had done something wrong. The answer was negative. Recommendation; attention to detail by the initial RADAR Controller who issued the climb out instructions would have alleviated the wrong scratch pad information. The Local Controller should have been looking out the window to ensure all aircraft were on correct headings. The Local Controller had the last opportunity to save the situation. A quicker frequency change to Departure Control would have allowed the two controllers aware of the situation to rectify it prior to the dangerous proximity. However; procedures dictate the Local Controller shall not switch the frequency of a departure until the departure 'tags up' on the radar scope. This procedure proved to be more of a detriment than an asset in this situation. The Aircraft Y Controller and I both had to wait as the situation developed as we were not talking to either aircraft.