Wow that's a really nice bike, the 05' shifters look great.
The left unit is for the front (like the brakes). The right unit is for the rear. The large lever always moves you to a larger cog. The small lever always moves you to a smaller cog. The upshifting and downshifting is completely opposite because of this.
So for the left (front) unit, the large one moves you to a large chain ring (upshift), the small moves you to a small chain ring (downshift).
On the right (back) unit, the large one moves you to a large cog (downshift), the small moves you to a small cog (upshift).