A C-182 pilot on a sight-seeing flight was advised by the ATCT Local Controller of a close encounter with a Citation which passed several hundred feet above him unbeknownst to him.

Narrative

I was traveling from east to west at 2;600 FT outside of the ZZZ airspace. I was monitoring ZZZ Tower but was not aware of the fact that a Cessna Citation was above me in descent to Runway 2R. When the Controller called me and asked if I saw the traffic; I responded that I did not. Even though I was scanning and should have been aware of the traffic. The 182 is a high wing aircraft which makes spotting traffic above difficult but nonetheless; I missed it. When I landed I called the Tower and discussed the situation and the Controller said that even though I did nothing wrong; that a call up on the transition from southeast to southwest might have made the transition safer and easier for all concerned. I had a young passenger and his father aboard and that may have been a distraction at the time; but my only job is the safe operation of the aircraft. Usually I use flight following on these 'sightseeing' and 'orientation' flights but since this was to be such a short one I just monitored the Tower frequency. The passengers asked to stay up longer and at that time I should have asked for flight following. I will always go to approach for VFR flight following once the frequency change from Tower is approved.