Ah, my mistake, there was an extra setting I had to enable for members to be able to attach files. You should see an extra link under the word count on the edit box.
Vanilla comes with wysiwyg editor that I had enabled at first but it totally blows. Worse than nothing. The good news is there's a really kickass wysiwyg available for the upcoming version, but I don't want to upgrade to the new version until it's out of beta, and so I'm not sure how long it will be before we can easily format posts. In the meantime, though, if you know any basic HTML, you can format your posts that way.
Oh, and another thing, should there be another Members Only section for non-journal posts that people want to keep inside this community, or is it cleaner to just keep anything private in the Journals section?