Have you checked out the Livejournal Manual? That link will direct you straight to the part you want to read, I went through it, its really easy, it tells you everything you need to type.

A great deal of open source web-based software is written in PHP with a MySQL back-end. However, livejournal seems to be written in the perl language with a MySQL back-end database.

In any case, are you looking into installing livejournal, or something LIKE it. Because as far as I can see, livejournal runns off of THEIR servers, despite the software being open source? Check out http://www.livejournal.com/code/ to download the code for use on your own server.

Check out www.hotscripts.com and search for blog software. Otherwise, check out www.sourceforge.net for blog software. You might have better luck searching for "blog" software instead of "journal" software because they're the same thing and blog just seems to be the more used term.

http://www.myphpblog.org/ looks promising. iBlogger is a barebones multiuser weblog system, a little more advanced. There are a bunch more on http://php.resourceindex.com.

from what i understand you want to make ur own journal comunity for others to join and you need someone to help.

fastest thing that comes to mind is that if ur serious in doing so you can always employ someone to make one for you.
you would need someone who has a knewledge of html and php.

your other option is that if you are willing to pay for the server i'm sure lots of programmer are willing to create the site for you in return for a share of what it could bring.

some ppl might just do it for free. very rare but you might get lucky.