I started working on scripting support in Lokalize several months ago, but never really announced this because I wanted to write my own scripts and refine/extend API accordingly along the way.
KDE 4.3 will bring us 'officially' scriptable Lokalize. Among recent additions are new project wizard with anonsvn checkout support (screencast; it also checks out templates/ and scripts/ folders), actions to update .po from template and to compile .po into .mo and place it in local .kde folder so it could be picked up automatically by applications on the next start (see here and here for python sources).
Recently I also extended pology with ability to communicate to Lokalize, so now you can run xml checks against your translations and get erroneous files opened in Lokalize and positioned on appropriate entry.
So how it works: on each project open Lokalize scans PROJECTDIR/lokalize-scripts folder for .rc files and adds them to a 'cache' file called PROJECTDIR/lokalize-scripts/scripts.rc (so you shouldn't generally want to add it to version control system). RC files contain descriptions of scripts, particularly their paths. The path is relative to .rc file folder (or to a system scripts folder - they are tried both). So you for example can specify "../../scripts/lokalize/opensrc.py" to load script from global kde-l10n4 scripts folder (i.e. not specific to your language). Each script is represented with action in application menu (and you may assign a shortcut to it).
Below are links to API references. Everything marked as Q_SCRIPTABLE may be used from scripts
Editor object API reference
Lokalize object API reference
Project object API reference
You are welcome to write your own scripts and polish existing ones.