I'm doing some research on Tripwire, AIDE and some other approaches to host-based IDS (file status monitoring and such).

Free, open source stuff only, thanks.

I found some things on SourceForge, including Labrador (which seems to be just getting a leg up, so to speak).

I'm looking for any suggestions or direction others have taken or products used. Since we are budget challenged, we are looking for open source, freeware or whatever, and need cross-platform (that's why Labrador looked good). We have Linux, Unix (HP-UX), Solaris, and Windows servers.

Any suggestions or ideas are appreciated.