Sounds like great news for indie devs!
http://steamcommunity.com/greenlight
It seems you can even submit an early game concept to get feedback - all you need in order to submit a new game is the following:
- A square branding image (similar to a box cover) to represent your game in lists and search
- At least 1 video showing off your game or presenting your concept
- At least 4 screenshots or images
- A written description of the game along with tentative system requirements