The Royals ended their Championship campaign on a high at the Madejski Stadium.
The winger drove an incredible 35-yard free-kick into the top corner midway through the second half but the goal proved in vain as Reading picked up another win.
Jimmy Kebe may have spent the best part of two seasons frustrating fans at the Madejski Stadium with his lack of end product but the winger has been in outstanding touch since Christmas and opened the scoring with his 12th - and best - goal of the season.
Jobi McAnuff soon added a second as Brian McDermott's side eased to a victory over Darren Ferguson's side with Gylfi Sigurdsson and Simon Church netting late on.
Reading's form since knocking Liverpool out of the FA Cup in January has been exceptional and there can be no doubt that they should be regarded as promotion candidates next year.
Preston goalkeeper Andy Lonergan was ruled out with a groin injury to end a run of 147 consecutive appearances and replacement Wayne Henderson was beaten in the 12th minute before he had touched the ball.
Kebe has looked a different player under McDermott and added another fine goal to his collection.
The Mali winger collected the ball flush to the right touchline and was shepherded inside by full-back Tom Williams. Kebe sprinted in on goal and after evading two more half-hearted challenges lashed a low left-footed shot past Henderson and into the corner for his 11th goal in the last 25 games.
It was a fabulous solo effort which has been typical of the Royals' play in the second half of this campaign.
Preston's afternoon got worse moments later when midfielder Barry Nicholson hobbled off with an injury and McAnuff soon swept Reading further ahead with the second in the 17th minute.
Reading's wing play has been outstanding since the turn of the year and when Shane Long picked out McAnuff in space down the left, he tormented Billy Jones before coming in on his right foot and curling a strike wide of Henderson.
Alex Pearce was denied a third by a sharp stop from Henderson and Kebe then should have scored when Long's shot was parried into his path.
Henderson last started for North End in August 2007 but was making up for lost time as he made another superb save to keep out a Long drive.
The hardy band of away fans were by now making their own entertainment and won a healthy round of applause from the Reading fans for a fancy dress conga led by Scooby Doo and Bananaman.
Back on the pitch, Long blasted another good chance over the crossbar before Wallace wasted a great chance for the visitors.
A Reading corner was cleared and Andy Griffin made a hash of gathering the loose ball on the halfway line to allow Wallace a free run on goal. The former Sunderland winger sped away but shot against the base of the post.
It was a poor effort from Wallace but he soon had the whole ground applauding with one of the goals of the season in the 64th minute.
There looked little danger when he lined up a free-kick at least 35 yards from goal but Wallace hammered an unstoppable strike past Adam Federici.
Reading responded quickly with player of the year Sigurdsson claiming his 20th goal of a fine campaign in the 72nd minute.
Kebe was again involved, testing Henderson with a powerful shot and when the rebound fell to Sigurdsson the midfielder squeezed his shot in off the far post.
Substitute Church then added a tough of gloss in stoppage time when he turned and thrashed a dipping volley over Henderson and into the roof of the net from 20 yards.