To use avahi in Archlinux, first pacman -S avahi
then add it to your DAEMONS in /etc/rc.conf as avahi-daemon
you also need the capability module to be loaded, so add it to MODULES array in the same file.
you can grab gshared from [community] and have shared files between the lan, with no configuration, no hours in samba hacking no nothing. just works
for windows machines to know of zeroconf use www.apple.com/support/downloads/bonjourforwindows103.html