You can download it from the website < http://www.integrativemodeling.org/download.html%3E or access the source from git at https://github.com/salilab/imp.git (use the master branch). For those of you building from source, we now use CMake to build. See < https://github.com/salilab/imp/wiki/Cmake%3E for more info.
For the future, IMP will have releases every 6 months. In addition, we will provide patches to the latest releases as necessary to fix important bugs that are encountered.
You can find some more resources in the documentation < http://www.integrativemodeling.org/2.0.0/doc/html/%3E and the wiki < https://github.com/salilab/imp/wiki%3E. If you encounter bugs or other difficulties, please open an issue on github at < https://github.com/salilab/imp/issues%3E, or email the imp-users list.
There have been lots of improvements since 1.0. You can view the change history at http://www.integrativemodeling.org/2.0.0/doc/html/recent.html.