This is my first post from that app, so let's see how it goes. I'm most interested in seeing if autoposting of multiple images works (in the past, in Facebook for example, a new album would be created by PicPosterous with just the first image, the rest would all make it to posterous but not facebook). To test this I've added two hopefully prescient screenshots from the incredibly awesome and devilishly addictive iPhone game, "game Dev Story". If you haven't checked it out yet, do so now (but first warn your loved ones they may not see you for a couple of days. Or weeks)!
From an editing point of view, the new posterous app uses the standard iPhone editor (so no text styling), and allows enabling or disabling geotagging, autoposting and private settings for the post. Tags can be added (with a nifty chooser that shows past tags), and of course media can be attached. At this stage only photos and videos can be attached (new or from the library) but no audio recordings. There's also unfortunately no multiple-select for images and videos, so each has to be added individually.
In addition to posting to any of your posterous blogs, the app also allows you to view past posts. I've yet to check if they can be edited, and since there's no way to save a draft, I'll try it after posting this.
Like posterous itself, the app is dead simple and intuitive, just what you need (well, most of it) and no more.