Check the similar threads section below; there have been a couple about Beer Wars. The one time showing is done by a company -
Fathom - that does other events like broadcasting operas from the Met live into theaters around the country. One of the downsides to this, apart from there being only one showing, is the cost - I think tickets are $16 here. I've heard $15 from some people.
The actual movie will be followed by a live panel discussion (30 minutes, I think) involving several people from the movie. It should be interesting because the panel, though they're all in the movie, will be watching it for the first time along with everybody in the theaters. You'll be seeing their real, immediate reactions to how the film turned out.
It will be on DVD eventually (later this year, maybe?), but I don't think they're planning on including the panel discussion on the DVD. Of course, that could change and I think it'd be a neat extra to have on the DVD.
More info at the
Beer Wars movie site.