From today it is possible to filter the games in the Steam Store by the supported VR headsets, play space and input devices that come with VR. There aren’t many games showing up when you enable the filter. There are a lot more games compatible, but the publishers have to select the new option from there distribution page on Steam. Soon we’ll see hundreds of VR capable games.
At the time of writing there is a total of 19 Vive games and 23 Oculus Rift games availble.