There is some facts about current OVAL support in deb-based distributions (Debian and Ubuntu):

• Ubuntu 8.04 Hardy released with oval-interpretator 5.3 in universe section
• oval-interpretator 5.4 already migrated to Debian testing and ready to ship with Lenny
• oval-interpretator 5.4 migrated to Ubuntu unstable repository and will include in next releas

In next phase we plan to add official support status to OVAL definitions for Debian and Ubuntu distributions.