The embedded widget is in alpha...
The default prefs are
chatOutputShowTimes = false showJoinsParts = false showAwaysBacks = false chatOutputNickWidth = 90 userListWidth = 130
You can override all of these in the URL, using params. You can also override autoAway. eg &autoAway=0 to disable
Then, just specify channel and optionally nick. If you do not provide a channel, it will go to #chat If you do not provide a nick, a random one will be chosen If there is a nick collision, the user will be prompted to choose a new one (IE7 may have issues with prompt)