For the impatient and those that just don't want to bother with compiling from source in order to use a newer version of Xastir, there's a user provided binary package that can be installed with only a few mouse clicks.
The binary package for Xastir that is available in the Ubuntu 12.04 or repository is older and lacks the latest updates.
Providing a more up to date alternative, the latest user-provided Xastir binaries can be downloaded via the links below:
Note: the above package is a 32 bit version - it will not install in the 64 bit version of Ubuntu.
The binary (deb) package is installed using the Ubuntu Software Center - simply double-clicking the deb file in Ubuntu 12.04 will launch the Software Center, which prompts the user to install.
Note: This version of Xastir installs scripts in /usr/share/xastir/scripts instead of the previous location of /usr/lib/xastir. After you are up and running on this version, you can delete /usr/lib/xastir.