msn.netlab.cz, icq.netlab.cz and sms.netlab.cz are transports. You must go in "service discovery" in your jabber client, and right-click -> register on them. Then you enter your address & password (me@hotmail.com and your msn password) and AUTHORIZE ALL CONTACTS !!!!! (otherwise you loose them). A good idea is to use PSI for this, even if you don't use it to chat, and BEFORE REGISTERING, chec the "auto-authorize contacts" checkbox in the config, then register, and then uncheck it. If some contacts have a cross or similat, right-click -> request authorization from and right clrick -> send authorization to.
jabstatus@njs.netlab.cz is (I think) a contact, that gives you info about hte status of the different services of netlab.cz. All you have to do is add it to your contact list, and it should work a bit like the weather transport (I also posted an answer to your question about weather, so go & have a look). Maybe on the jabber.cz wiki you'll find roster icons so that jabstatus@njs.netlab.cz displays a tick when everything's ok, and something else when services are down. that's just an example.
There's no faq probably because this is mainly a czech site, and most of it isn't translated ^^.
See you !
~jahvascriptmaniac