Having lost last year's final to Crystal Palace, the Hammers were clearly determined to ensure that lightning did not strike twice and they dominated throughout as they deservedly climbed back into the top flight.
Just one place and two points separated these two sides over the course of a gruelling 46-game campaign.
And after finishing in fifth-spot, North End also held a psychological advantage over the Hammers following two feisty Championship victories in which there had been no love lost between the sides.
But straight from the kick-off, West Ham - who replaced Carl Fletcher with Shaun Newton following their semi-final victory over Ipswich Town - made sure that league form counted for nothing on the neutral turf of Cardiff's Millennium Stadium.
Indeed, after just four minutes, Nigel Reo-Coker played in the overlapping Tomas Repka who was denied his first goal for the Hammers on his last appearance for the club, when his eight-yarder crashed off Carlo Nash's left-hand post.
And as the East Enders dominated the early proceedings, Zamora tumbled under Claude Davis' clumsy challenge only for referee Mike Riley to wave away vociferous penalty claims.
Midway through the half, Zamora again caused problems when he released Matthew Etherington whose blistering 12-yarder was palmed to safety by Nash.
Apart from a couple of cleverly worked free-kicks, unchanged Preston struggled to threaten West Ham on the slippery surface. But just before the break, the hitherto redundant James Walker was relieved to gather Eddie Lewis' awkward corner when it arrived in his six-yard box.
Three minutes after the interval, another Lewis flag-kick caused the Hammers even more problems and only Newton's goal-line clearance prevented Richard Cresswell from heading the Lilywhites ahead.
Shortly afterwards, there was equal danger at the other end as influential United skipper Nigel Reo-Coker sent Marlon Harewood clear, and although Nash parried his shot, the ball spun to Zamora who saw his effort cleared off the line by Chris Lucketti before the grateful Preston 'keeper smothered Harewood's second follow-up.
There was to be no let off for the exposed Nash as the hour-mark approached, for when Etherington sent a low cross into the six-yard box, the supporting, alert, unmarked Zamora comfortably side-footed home his 13th goal of the campaign.
West Ham's scorer might then have added a second shortly afterwards but he wastefully headed wide.
As Preston desperately tried to rediscover a path to the Premiership, David Nugent saw his low 18-yarder comfortably saved before Richard Cresswell both volleyed wide and headed straight at Walker.
As the seconds ticked down, the consequently booked Hammers' 'keeper was then in the wars when he fell awkwardly after accidentally carrying a high up and under out of his area.
That was to lead to seven anxious, agonising minutes of stoppage-time for Alan Pardew's team, but Walker's replacement Stephen Bywater confidently held Lewis' subsequent free-kick and the Hammers held on to claim the deserved victory that now sees them make a daunting return to the Premier League following a two-season absence.