If all you require is a way to stream video and music to your Smart TV then Serviio as mentioned about should serve your needs.
Check out the features: http://www.serviio.org/features
However if you're looking at mirroring your MBA (or an MBP) to a Smart TV then I don't believe it is possible to do wirelessly (as yet). I've been searching for this solution also without any luck so far. It seems the only options are to buy an Apple TV and use mirroring or buy another third party device that can provide this function or use a HDMI cable which is kind of limiting.
When (and that a big WHEN or should that be an IF) Apple launch their iTV then it will most likely be possible to mirror directly to TV without the need for a HDMI cable.
So unless Samsumg come up with an AirPlay or Mirroring function update that will allow any wireless computer or laptop to connect to it then you're stuck with a HDMI cable as your only connectivity solution.