LiveJournal Search Plugin for Mozilla
This search plugin adds a "LiveJournal" search option to the search list found in Phoenix (and Mozilla, though I haven't tested that). Typing a username in jumps directly to that person's user information.
Click here to install the plugin.
To do so, your browser needs to be able to write into
lib/mozilla-version/searchplugins, so Unix users may need to temporarily change some permissions.