antichat.res.cmu.edu should work if services.antionline.com is temporarily out of order. If you use the java applet, type /server antichat.res.cmu.edu 6667 in order to get into the network, or try /server 128.2.154.239 6667
I know it works for mIRC, but the java applet doesn't seem to be able to do it for some reason... I'll try it again later.
If this post helped you get back to IRC, please bump it up so others can know too.