PRC Controller described conflict event at 6000 MSL; when VFR traffic; being worked by ZAB; was not transferred to PRC until four miles from the airport; resulting in a conflict with tower controlled arrival traffic. Reporter suggested realignment of airspace to prevent future occurrences.

Narrative

I was training on Local 1 with a low time Developmental Controller. An experimental aircraft called four miles northeast of the airport inbound on the ILS. We had a C172 approximately four miles northeast on a straight in. I observed a radar target right behind the C172 and ascertained that it was the experimental that just called. I took the frequency/position and I called the traffic directly ahead of the experimental and he did not have the traffic in sight. I was concerned about having a midair collision between the experimental and C172 and told the experimental to make a right 180 degree turn away from the airport to maintain spacing. I let the Developmental take the frequency/position back and he told the experimental to intercept final and the experimental was able to complete the approach to the airport. I later found out that the experimental was being given flight following on the ILS approach by ZAB and they did not give the aircraft a frequency change until four miles northeast of the airport. We continue to have issues with the airspace over Prescott Airport. Solutions; in order of preference; are 1. Let PRC ATCT have a TRACAB or approach control and work the airspace 2. Have P50 work the airspace