AS AN EMB120 IS LNDG AT ACV; AN SMT DEPARTS IN OPPOSITE DIRECTION; CREATING AN NMAC CONDITION. THE LNDG ACFT WAS ON THE WRONG CTAF FREQ BECAUSE THE APCH CHART HAD THE WRONG FREQ PRINTED.

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FLEW ILS RWY 32 TO ACV ARPT. ENTERED VISUAL CONDITIONS OUTSIDE OM. ZSE ADVISED US TO 'SWITCH TO ADVISORY FREQ.' WE TUNED VHF FREQ 123.00 AND SELF-ANNOUNCED IN ACCORDANCE WITH AIM PROCS. OUR MAP REVISION DATED OCT/XX/98 INDICATED THE CTAF FREQ FOR ACV IS 123.00 (A CHANGE FROM 123.50). ON SHORT FINAL; I NOTICED AN ACFT DEPARTING RWY 14. (WE HADN'T HEARD ANY ACFT ANNOUNCE DEPARTING ACV.) I PERFORMED A MISSED APCH TO THE R WHILE THE DEPARTING ACFT COMMENCED A R CLBING TURN. AFTERWARDS; I FLEW L TFC WHILE MAINTAINING VISUAL SEPARATION WITH THE OTHER ACFT (A TWIN CESSNA). SUBSEQUENT DISCUSSION WITH ZSE REVEALED THE UNICOM/CTAF FREQ FOR ACV IS INDEED 123.50 NOT 123.00. THE COMMERCIAL CHART REVISION WAS WRONG. NO NOTAM WAS ISSUED CONCERNING THIS. APPARENTLY; OTHER COMPANY PLTS WERE ALSO USING 123.00 (THE WRONG CTAF FREQ). I DISCUSSED THIS WITH FLT CTL (DISPATCH) AND OUR FLT OPS PERSONNEL. COMPANY PLTS ARE BEING GIVEN THIS INFO ON THEIR FLT RELEASE. IN THE FUTURE; IT MAY BE PRUDENT TO LISTEN TO BOTH CTAF FREQS AFTER A CHANGE. IN THIS CASE; I WAS USING THE WRONG FREQ. BUT SHOULD OTHER PLTS HAVE BAD INFO; THEN I CAN LISTEN IN ON THEIR XMISSIONS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR WAS BOTHERED BY THE FACT THAT THE ARPT TFC DID NOT HAVE THE PROPER FREQ ACCURATELY PUBLISHED. HE REVIEWED IT WITH ARTCC AND THE CHART PUBLISHERS. HIS COMPANY WAS INFORMED AND THE WORD WAS SPREAD AMONG THE PLTS. IN THIS CASE; RPTR IS POSITIVE EACH ACFT SAW ONE ANOTHER; AS EACH TURNED AWAY FROM THE OTHER. RPTR FELT THAT THIS TYPE OF INCIDENT SHOULD NEVER HAVE HAPPENED. EACH ACFT WAS PROBABLY MONITORING A SEPARATE FREQ. THE DEPARTING ACFT HAD THE WORKING FREQ AS HE WAS PROBABLY STATIONED AT THE ARPT. THE ARRIVING ACFT WAS USING PUBLISHED FREQ WHICH WAS INCORRECT.