The GIMP Animation Package, or short GAP, is a collection of plug-ins to extend the GIMP with capabilities to edit and create animations as sequences of single frames. The plug-ins used to be part of GIMP 1.2 and you probably missed the Video menu in GIMP 2.0 already. Here is the stable release to go with GIMP 2.0. There are a couple of new features including a new bluebox plug-in, onion skinning and a video preview.