Red Bull Racing have kindly provided through twitter a detailed graphic of their 2015 Formula 1 steering wheel used by Daniel Ricciardo and Daniil Kvyat on the RB11. I'd be lying if I said I wasn't overwhelmed with the complexity of the steering wheel even after Red Bull have so kindly explained it.
Every team on the grid now runs an LCD display for sending more detailed information, especially since the ban on in-car driver coaching. Williams, interestingly enough, have mounted theirs directly to the chassis, more akin to your instrument cluster in your personal car, thus freeing up their steering wheel for only buttons and knobs.
Note the two clutch paddles on either side underneath the up and down shift paddles.