Remember Gimp Animation Package? GIMP Animation Package is a collection of Plug-Ins to extend the GIMP with capabilities to edit and create Animations as sequences of single frames. GAP version 2.6.0 was released a while back and at the time, you needed to compile the package to be able to use it but now there are Ubuntu .deb packages available which you can use for a one-click install of Gimp Animation Package:
Download GAP for Ubuntu Jaunty 32 bits
Download GAP for Ubuntu Jaunty 64 bits
Download GAP for Ubuntu Jaunty 32 bits
Download GAP for Ubuntu Jaunty 64 bits