I'm using pwsafe (Password Safe) on my n800 with OS2008. It's not the prettiest application, and the interface isn't very user friendly, but it does the job and is hildonized.

On the WinXP side, I'm using Password Gorilla. It's available for Windows, MacOSX, and Linux. It reads databases created by Password Safe AND has an option (Manage->Database Preferences...->Uncheck "Use Password Safe 3 format") to save databases in the older (v2) format of Password Safe. This is important because the n800 version doesn't read v3 of Password Safe databases.