The problem is that your prop shaft isn't parallel with the surface of the water and you're getting torgue steer from the propeller angle.
As you come up on plane, begin to trim the outboard UP in little bumps of the button. Keep doing that until you notice that your bow starts to bounce up and down (called porpoising). Then bump down a little until that stops. Now, watching your RPM gauge, trim up or down to max out your rpms. When you aren't porpoising, or experiencing torque steer, and your RPMs are as high as they will go for a given throttle setting, your shaft will be parallel with the water. As you add more throttle, you may need to trim up a bit more.
One hint: don't look at the trim gauge the first few times you do this. Find the "sweet spot" soley by the seat of your pants and the RPM gauge. Once you can peg the sweet spot consistently, then look at the trim gauge. From then on, all you'll have to do is get up on plane, trim until the needle is where it's supposed to be and Wa-LA!!! No more torque steer!
