[csense]

Put it on your website and take payments in the form of Paypal/credit card/bitcoins/whatever in exchange for a download link.

If you want to sell for Android (which is, of course, a type of Linux), try the Google or Amazon app stores.

Dominions 3 [1], a commercial game with a native Linux build, recently changed publishers and is now sold on Desura [2].

If you enjoy making your users put up with horrible DRM, I've seen multiple HN articles about how Linux support for Steam is in the works.

[1] http://en.wikipedia.org/wiki/Dominions_3:_The_Awakening

[2] http://en.wikipedia.org/wiki/Desura

[jdjb]

"If you enjoy making your users put up with horrible DRM, I've seen multiple HN articles about how Linux support for Steam is in the works"

It's an open beta right now with about 40 games listed under Linux.