PA28 pilot at 5500 feet reports NMAC with opposite direction C172 while using flight following with Fayetteville Approach. The Controller called the traffic only moments before the near miss.

Narrative

Today I was flying using VFR flight following radar services. About halfway to my destination; while talking to Fayetteville Approach; I had what I would classify as a 'near miss'. I was at 5;500 FT; cruising at 110 KTS true airspeed scanning regularly for traffic; and so far hadn't seen much of anything near me. Then; out of nowhere Fayetteville Approach radioed 'traffic at 1 o clock intentions unknown confirms you see it!' By the time I looked outside a Cessna Skyhawk buzzed by nearly head-on past my right wing. We came within maybe 100-200 FT from colliding with each other. More advanced warning from approach would have been helpful since the frequency was not all that busy. I don't know why ATC was not paying more attention but the warning was too late to prevent a possible collision. The angle it came from was slightly below the windshield so there is no way I could have visually seen the traffic until it was too late to change course. What is very troubling is that we were on a correct altitude for our heading following the rule 'Odd altitude +500 FT 0-179 degree headings; and Even altitude +500 FT 180-359 degree headings'. The other pilot should not have been anywhere near us heading in the opposite direction (northwest) so he was a contributing factor as he was violating VFR altitude heading rules. As far as my end goes no violations of FAA regulations was committed by me. I am filing this report not because I am concerned about punishment from the FAA as I did nothing wrong; but rather because I hope it will help to create more safety initiatives aimed at making VFR pilots who aren't talking to anyone more aware of the dangers associated with flying non-standard altitudes and hopefully choose not to do so.