http://www.apcupsd.com/ 

Looks like all ditros have had the apcupsd ported to them, but testing has only occured on Red Hat, 
Solaris, FreeBSD.  Also appears that all APC models are supported w/ the latest version.  They all 
use the same control lang., just  the newer and more expensive versions have more commands or 
provide more info.  Apparenly, if you have an old APC, the only info it send over its serial cable 
may be that voltage has dropped, so it's time to shutdown.

For Powerchute which is free:
http://www.apcc.com/products/management/pcp_linux.cfm 
http://www.apcc.com/tools/download/

Brian Kelsay