Time to celebrate! ROS 0.5 is here! You can download it from ros.sourceforge.net.
We've been working furiously on ROS to incorporate new features and APIs to make ROS easier to use and more robust. The biggest change is the introduction of the roscpp "Node Handle" API, which is based on months of feedback from the ROS community and our own internal testing. There's also a new, experimental roswtf tool, which we hope to evolve into a powerful system-wide diagnosis tool. To find out more about this release, please read the list of changes.
This release also marks the start of our 'stack' releases. In the coming weeks, look for our first release of ROS Stacks, which are collections of ROS packages that are now mature enough for release to a wider audience. One of the first stacks that we will release will be the Navigation stack, which was heavily tested and refined during Milestone 1.