Now you have Icecap installed and you're eager to use it. Since most clients don't yet have the proper functions to add network/servers/channels we'll have to do it ourselves.
Put this into ~/.icecapd/startup
network add;network=<network name>;protocol=irc gateway add;host=<network server>;network=freenode;port=6667 presence add;network=<network name>;mypresence=<nick>;real_name=<Real name>;autoconnect channel add;network=<network name>;mypresence=<nick>;channel=<channel>;autojoin;out_charset=utf-8;in_charsets=iso-8859-1
Substitute <whatever> with your whatever.