GIMP has released the first release candidate of GIMP 2.8. Here’s the release note:

We released new versions of GEGL and babl, quickly followed by the first release candidate of GIMP 2.8.
GEGL 0.2.0 has some major improvements and breaks API/ABI compatibility with earlier versions for some very good reasons.
Perhaps the most exciting change in GEGL is an initial support for GPU-side rendering and processing via OpenCL. Hardware acceleration makes it possible to leverage many operations to GPUs which can dramatically improve performance.
The foundation for this feature was laid by Jerson Michael Perpetua as the primary objective of his GSoC2009 project. The second part of the project was done by Victor Oliveira during GSoC2011. Victor was also sponsored by AMD to finish the project this winter, with help from GEGL team, Zhang Peixuan and his team from Multicore Ware. Currently you need to run GEGL_USE_OPENCL=yes to use this.
Two new essential operations were contributed to GEGL. Mikael Magnusson implemented perspective transformation, and Jan Rüegg submitted a global matting operation that would be required for a GEGL-based foreground selection tool.
Since this version GEGL also supports internationalization. The final patches for that were delivered by Michael Muré. Translations into German, French, Polish, Russian, Slovenian and Spanish languages are available, and we expect more to follow. Users of GIMP 2.8 will see this in the experimental GEGL operation tool.
The changes in GIMP 2.8rc1 since 2.7.5 are mostly not user-visible. We merely updated the code to work with newer versions of GEGL and babl, fixed GFig rendering issues and used all the translation updates we got to the point. There is still time to review your translations and submit updates, although probably not too much of it.
Please use the Downloads section to fetch source code of GIMP 2.8rc1 and visit for source code of GEGL and babl. Let us know if you run into serious regressions that haven’t been reported yet.

Install gimp 2.8.0 rc1 in Ubuntu Precise and Oneiric from ppa:

You can install gimp 2.8.0 rc1 from this untrusted PPA (support for Ubuntu 12.04/11.10). The PPA could break your installed OS, please use it at your own risk.

In a terminal window, execute following commands adding the ppa and install gimp:

sudo add-apt-repository ppa:otto-kesselgulasch/gimp
sudo apt-get update
sudo apt-get install gimp

For Ubuntu 11.10, you may need this package installed frist:

sudo apt-get install libgdk-pixbuf2.0-0