Currently we are releasing Nightingale versions our website :
They are hosted on sourceforge.net
Plus, we also have (unofficial) Linux distribution packaging :
A request have been made to distribute Nightingale on Steam :
https://github.com/nightingale-media-player/nightingale-website/issues/29
The cost to submit is 100$, but being on Steam would definitively be a big plus for us.
Thought before this we have to make sure the product is usable without any nasty bugs.