Omega T+ is a suite of computer assisted translation (CAT) tools designed to facilitate and streamline the translation process.
It's worth noting that you'll need a Java Runtime Environment (JRE) to use omegat. You can obtain this separately from Sun Microsystems or another vendor; on Linux, a version called Blackdown is available. If you already have a JRE installed, make sure it's up to date (check the omegat Users Manual for installation details). Mac OS X users have a JRE installed by default.
If you're interested in software development in Java, a Java Software Development Kit (JDK) can also be used (it already includes a JRE).
The latest release has a change to the version numbering system, moving to 3 numbers. Unfortunately, the user manual had to be removed due to licensing issues, but a new one is currently in development. Finally, this release includes minor bug fixes.