You can setup a
host on your network to host a proxy autoconfig (.PAC) file and then have
browsers on your network find it relatively easily. Basically you just need to have
http://wpad/wpad.dat resolve on your network to your proxy autoconfig
file, so you just setup a DNS entry for wpad (or use the hosts file but
it hardly seems worth it, since you’d have to do that on each client
machine).