I've also ruthlessly torn apart Opi's last entry made in XML, and think I've figured how it works, so I'll likely be playing with converting this and my two previous into that format. ...When I say play I mean it will work, come hell or high water, by the way.
At any rate, here's what I knocked together for viewing journals. If I'm stepping on someone's toes, just smack me around a little then point me to a more recent listing of guides being worked on.
Comments welcome, etc. :)
Viewing Journal Entries
The most common way of viewing journal entries is to go to the journal. To do this, you type the address of the journal into your browser, http://www.livejournal.com/users/username where 'username' is replaced with the username of the person's journal you want to read.
From that page you will see the journal laid out as the user wished. The latest entry made into the journal will be at the top, with the entries getting progressively older going towards the end of the page. The view you are seeing here, is called LASTN, or Most Recent.
Depending on the style the user has chosen, the links could be at the top, or bottom, but somewhere there will be a link to go back a certain number of entries. The default being 20, but the user can customize that number. If you click on that link, you will see their LASTN page load again, with older entries shown this time. You can continue clicking on the back link to view older and older entries, up to 75.
The livejournal servers keep the last 75 entries of a user is a ready-to-view format, which can be thrown up onto the LASTN view in order. Once you pass 75 entries, however, livejournal will stop using LASTN view, and beyond that, will switch into what is called DAY view. This view, as the name suggests, only shows one day at a time, clicking back will take you to the day before, clicking next will take you to the day after. If no journal entries were made that day, you will be given a message stating that.
This is not the only way to reach DAY view. You can also reach DAY by going through CALENDAR. On any view of a user's journal there should be a link to their calendar page. Which will show you what looks like a calendar page with numbers under the dates that are links. The numbers signify how many journal entries were made on that particular day, and clicking on the link will take you to the DAY view for that date.
Also found on the Calendar page, there will generally be a link to View Subjects. If you click on this link, you will be taken to a page showing all posts made that months by their subject, and the number of comments, if any. Clicking on the subject will take you to that post so you can read it. Clicking on the arrows at the top of the page next to the month will take you back to the month before (left arrow), or forward to the month after (right arrow).
The view you are shown when you click on the subject in the month view (or by clicking on the link to read comments in LASTN or DAY view) is for reading comments. You can also post a comment by clicking on the appropriate link on this page. Towards the top there is a bar of icons, with two arrows, you can also use these arrows to navigate a person's journal by entry. Clicking on the right arrow will take you to the journal entry posted after the one you're reading. Clicking on the left will take you to the one before.
Another way to view a person's entries is to add that person to your friends list, and read their journal (Along with everyone else listed as your friend) on your friends page. The FRIENDS view can be gotten to by clicking on the link available from the main journal page. You can also add yourself to your own friends list, and reads you own journals along with all of your friends on this view.
Public, Private, and Protected Entries
Users have the ability to make their entries private, meaning only they can see them, or protected, meaning only people they have listed as their friends, or certain custom groups of their friends will be able to see the entries. Posts that are made like this are generally signified by little icons. A little padlock means it is a protected entry, and only friends can read that entry. A little eye means it is private, and only you are able to see that entry. Note that you must be logged in to read these entries.