Is there Help documentation for LifeJournal Online?

Yes, from within the LifeJournal Online application you can click the HELP link in the top right navigation bar.
There's a FAQs for LifeJournal Online page at http://www.lifejournal.com/faqs-for-lifejournal-online/ and a Help by Features page at http://www.lifejournal.com/lifejournal-online-ljo-by-feature/