It's very easy stuff.
1. Save the log using AIM. It will save as a .html file.
2. Open the .html and copy everything in it.
3. Paste it to a word file. If you don't have word, you could get Open Office which works just as well, if not better. It's also free. :D
4. Now, this is the bitch part. Delete all the Ds on single lines, along with the screen name that posted it, so that you have an empty line between each posted paragraph. Yes, this takes forever. Yes, it's annoying. We all hate it. But it breaks up the paragraphs so they're easier to read.
5. Now for a slightly easier part. Open find, using alt-f or however else your program finds stuff. Type in the screen name of one person, and have the program replace every instance of it with the player's chara name. For example, if I were to do it for myself, I would type "hoshi no saku" into the find query, and put in the replace with query "Kaoru". Don't do anything to the :. If you can not do find, you're kind of screwed. Since you don't want to have to replace every single name yourself, send it to someone who can do it for ya.
6. Save~!! Eek~!
7. Go to Livejournal, log in as yourself. Copy-paste the formatted log into the update window. You're done~!! Don't forget your eljay cut~!!!!!