It used to be there but now it's not! I tried logging in today through my steam account, but there isn't a checkbox thingie saying to login through steam, it's only a username and password thing.
I reinstalled and it is still stuck on username and password mode, instead of going to the log in screen for steam. :s
This is an intermittant problem. Restarting Steam will usually restore the log on screen to the correct state.