A C-152 pilot experienced an NMAC with a PA-32 while on flight following with ATC.

Narrative

I was released from the Tower and contacted Point Mugu Approach from who I received VFR flight following; radar traffic advisories and received a transponder code. The Controller called out some traffic for me a few times that were not really factors and I reported contacts on both.At 3;000 FT; I leveled off to clear the area prior to continuing the climb and; within seconds; spotted a PA-32R at my 12:00 on a directly opposite course and the same altitude closing at less than three football fields. I banked hard to the right; pulled power and dove. The PA-32 passed off to my left. He never changed course or altitude; and I believe he never saw me. At the time of my evasive maneuver I was about 600 FT from the PA-32 and maybe 300 FT when it passed off to my left. I never got a warning of this traffic from Mugu Approach. When I notified them of the near collision; they had no comment.In the future I will continue to lower my nose to clear the area during climbs but it will be between VFR and IFR cruising altitudes (e.g.; 2;700 FT; or 3;300 FT; etc.). This may provide a little more safety margin if there is a possible collision factor with someone in cruise or cruise transition. Also; I will try to avoid direct routes to and from airports while climbing and descending.I know Approach and ATC have there hands full at times; but I thought they had collision warning alarms and other practices in place when planes were converging at very close distances; especially at the same altitude; and if one or two of them are in contact and have assigned transponder codes. I would hope that lack of warning in cases like this is an anomaly and that all the aforementioned practices and tools in place are consistently being used.