It was the Italian's first pole position and he will be joined on the front row by in-form Briton Jenson Button in a BAR.
Although Ralf Schumacher, last year's pole-setter in a Williams, qualified second fastest the German loses 10 places on the grid after having an engine replaced on Thursday.
Trulli's Spanish team mate Fernando Alonso will be third on the grid, pushing Ferrari's six times world champion Schumacher down to fourth place.
It will be the first time this season that the German has not started on the front row after five poles in six races.
Schumacher is bidding to become the first driver to win the first six races of a season after equalling Nigel Mansell's 1992 record run of five in a row at the last race in Spain.
He is also hoping to equal the late Brazilian champion Ayrton's Senna's six wins in Monaco.
McLaren's Kimi Raikkonen, last season's runner up in the championship and in Monaco, starts on the third row alongside Brazilian Rubens Barrichello for Ferrari.
