Since googletalk supports jabber much of the information on this page may be obsolete. I tried the link to xmmp.net mentioned here, but couldn't connect (the error message indicated server problems, but it has lasted for four days now - maybe the link is broken?)
Then I followed the link to the wikipedia page, found a server and got an account. I don't know if it works, but at any rate the interface that I worked with in Kopete seemed to differ a bit from what is described here.
It would be very helpful to get feedback from a user, who has actually used jabber transports. Should we put an info box on the page warning that the information may be outdated and asking for help?
KDE UserBase Wiki 