Talau scored the first try of the game - and set Saints on their way to victory
Bradford: (4) 14
Tries: Evans, Tupou, Vagana
St Helens: (17) 35
Defending champions St Helens put in an outstanding display in both attack and defence to seal their place in the Carnegie Challenge Cup final.
Tries: Talau, Meli, Gidley, Clough, Pryce, Bennett
Goals: Long (3), Pryce, Wellens
In a cracking game at the Galpharm Stadium, Saints opened up a 17-4 lead at half-time thanks to tries for Willie Talau, Francis Meli and Matt Gidley.
Bradford scored the first try of the second half courtesy of Tame Tupou.
But Saints crossed through Paul Clough, Leon Pryce and Mike Bennett to make the first final at Wembley since 1999.
It also means that Daniel Anderson's team are 80 minutes from defending their title after their victory over Huddersfield in last season's final at Twickenham.
They will play either Wigan or French side Catalans Dragons, who meet in the other semi-final in Warrington on Sunday.
In truth, though, whoever play Saints will be hard pushed to beat them on the evidence of their performance against Bradford.
Saints were awesome in attack, playing with a guile, speed and fluidity that a willing and powerful Bulls side struggled to contain.
A break from Pryce and a brilliant miss-pass from man-of-the-match Keiron Cunningham, playing in his 400th game for Saints, culminated in Talau touching down in the corner after three minutes.
Bradford came back strongly and reduced the deficit when James Evans collected a deft and wonderfully-weighted grubber from Paul Deacon.
But the Bulls all too often struggled to translate their periods of supremacy into points, while Saints looked like scoring every time they attacked.
Poor defensive positioning contributed to Meli touching down in the corner before a brilliant break from James Roby and a sublime reverse pass from Jon Wilkin combined for Gidley to score.
It was a tough and physical encounter at the Galpharm Stadium
St Helens also allied intelligence to their considerable skill, as Sean Long demonstrated with a long-range drop goal after the hooter had sounded to extend his side's advantage at the break.
Saints were not all about attack. Bradford had large periods of possession and played with tremendous commitment, only to find themselves frequently repelled by superb defence.
Saints, however, could do nothing to prevent Tupou touching down after the break to reduce the deficit to nine points and give the Yorskhire side the hint of a comeback.
The Bulls, though, were often masters of their own downfall and lost the ball immediately after scoring - their hopes of a fightback seemingly extinguished when Clough collected a delayed pass from Long to score.
Vagana bulldozed over to renew Bradford hope once more but Pryce immediately scored an intercept try, racing 60 metres to cross under the sticks, before Bennett collected a brilliant flat pass from Cunningham to put the seal on a superb display.
Bradford: Platt, St Hilaire, B. Harris, Evans, Tupou, I. Harris, Deacon, Vagana, Newton, Lynch, McKenna, Solomona, Morrison.
Replacements: McAvoy, Henderson, Burgess, James.
St Helens: Wellens, Gardner, Gidley, Talau, Meli, Pryce, Long, Fozzard, Cunningham, Graham, Gilmour, Bennett, Wilkin.
Replacements: Roby, Hargreaves, Clough, Fa'asavalu.
Referee: R Silverwood (Dewsbury).