I've written a bit of software (minimal, only just barely works) to shutdown
NetBSD on a signal from an APC Back-UPS.

http://www.capybara.org/~dfraser/backupsd/

Comments/suggestions/help are appreciated.

-- 
Dan J. Fraser <dfraser@mother.com> -- <URL:http://www.mother.com/~dfraser/>
Finger me for Geek Code/PGP public key.  IRC (irc.warped.net) nick: Optic
"The national flower of of America is the concrete cloverleaf."