The video quality of the broadcast is going to be extremely poor. The best video option for broadcasting is medium quality which is "watchable" but not the best.
You might not even be able to make out the names above the players or the server text.
Then again it depends on the upload speed of the broadcaster. You will also need a decent PC, and whoever is broadcasting needs to be aware that their ping is going to jump into the 200's-300's or even 400's
You open Xfire, bring up Xfire in-game, edit the broadcasting options/video and sound quality/broadcast hotkey, use the hotkey to start the broadcast, then on the Xfire website, you browse through the "Live" broadcasts and search for your stream. You can then link that stream to anyone whether or not they have xfire installed and they will be able to view it.