Gnash is a GNU Flash movie player. Previously, it was only possible to play flash movies with proprietary software. While there are some other free flash players, none support anything beyond SWF v4. Gnash is based on GameSWF, and supports many SWF v7 features.

The main developer's web site for Gnash is located on the Free Software Foundation's Savannah project support server. This site allows you to file bugs, or view the sources in CVS.
Features

    Runs standalone
        Gnash can run standalone to play flash movies.
    SWF v7 compliant
        Gnash can play many current flash movies.
    XML Message server
        Gnash also supports an XML based message system as documented in the Flash Format specification.
    High Quality Output
        Gnash uses OpenGL for rendering the graphics on the desktop, and AntiGrain (AGG) for embedded framebuffer only devices.
    Free Software
        Gnash is 100% free software. For more information on the GPL, go to the Free Software Foundation web site.
    Better Security
        Gnash pays extra attention to all network connections, and allows the user to control access.

More information is available from the Gnash homepage at http://www.gnu.org/software/gnash/