The latest version of TestNG can be downloaded from Maven Central or here for ant users.
For the Eclipse plug-in, we suggest using the update site:
You can also install older versions of the plug-ins here. Note that the URL's on this page are update sites as well, not direct download links.
TestNG is also hosted on GitHub, where you can download the source and build the distribution yourself:
$ git clone git://github.com/cbeust/testng.git $ cd testng $ cp ivy-2.1.0.jar ~/.ant/lib $ ant
You will then find the jar file in the target directory
The beta version contains changes that have been committed to the repo since the current release.
Take a look at CHANGES.txt to see if the change you want is included in the beta (listed under "Current").
You can download the beta version here.