A light aircraft pilot reported an NMAC with another light plane in cruise flight at 6;500 FT in the vicinity of SJT. He was receiving flight following and was disappointed he was not alerted to the traffic by ATC.

Narrative

I was flying [my light single] VFR at 6;500 FT westbound from DWH to SJT. I was receiving VFR Flight Following from Austin Approach and was at approximately the CWK 073 radial at 29 DME fix at the time of the NMAC. I saw a single engine high wing airplane pass directly over the top of me; from south to north; at a [distance] of approximately 100 FT vertically in what appeared to be a steep descent. I fly regularly in very busy Class B environments and have never seen another aircraft that close to me. I immediately descended a couple of hundred feet and then was issued a traffic advisory. The Controller did not however issue this advisory until after the NMAC occurred and the other aircraft was off my three o'clock position and had already descended below my altitude. I believe that a position relief briefing was being conducted at the time of the NMAC. I realize that when flying VFR; I am responsible for seeing and avoiding other aircraft. I also know that VFR advisories are to be given 'as workload permits' and judging by the lack of other aircraft on frequency; there was plenty of time for the Controller to issue a traffic advisory. It would be my belief that the Controller was distracted while giving the position relief briefing and neglected to issue this advisory.