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 10.10 repositories is old and lacks key bug fixes as well as online OpenStreetMap support.
Providing a more up to date alternative, the latest user-provided Xastir binary can be downloaded via the link below:
Once downloaded, installing the package is as simple as double clicking the file in the file manager (nautilus). (It may be only a single click in Kubuntu)
The package is installed by the GUI installer, 'gdebi', which automatically installs required dependencies.