Jitsi (SIP Communicator) is still under active development and its first real release approaches. In order to learn the exact status of the development you could check out the Jitsi (SIP Communicator) Roadmap or join the announce mailing list. In the mean time you could try one of the following nightly builds.
Jitsi 1.0-beta1 stable build line
Microsoft Windows installers (32 bit version) (also available as a 64 bit version and as an msi)
MAC OS X packages
Ubuntu packages (you can also use our ubuntu repository)
Debian packages (you can also use our debian repository)
RPM packages
Arch Linux packages
Source code snapshots
Stable build line
If you are using our nightly build line, you can switch back to stable using the following provisioning URLs for Windows and Mac OS X
Jitsi 1.0-beta1 nightly builds
Microsoft Windows installers (also available as msi)
MAC OS X packages
Ubuntu packages (you can also use our ubuntu repository)
Debian packages (you can also use our debian repository)
RPM packages
Arch Linux packages
Source code snapshots
All nightly builds
If you are using our stable build line, you can switch nightly builds using the following provisioning URLs for Windows and Mac OS X
Note: We would like to support as many distribution specific packages as possible. If you would like to be a maintainer of such a package - please let us know