Pittsburgh Filmmakers in North Oakland bills itself as an independent media arts organization. What this means in practice is that they screen films, show photography exhibits, teach filmmaking & photography, and offer facilities and equipment to artists.
The films that they show at the Melwood Screening Room tend to be more experimental than what is shown at The Harris or at Regents Square.
Their classes are quite popular with local students (who can take them for college credit), independent artists, and hobbyists.
Finally, their artist memberships offer a great value for those wanted to work in the technical & equipment heavy fields of filmmaking & photography. A variety of digital and chemical facilities are available as part of a membership fee.
Overall, it's a great resource.