Not to long ago, Bitfire Systems created a native iPhone app that allowed Tumblr users to post text, images, and links for their friends to see.
Posting to Tumblr on Tumble was very easy–a lot easier than publishing to WordPress via iPhone.
Posting images from your gallery (or simply take one to include in a post) was simple and to the point.
Publishing links and quotes (which is sort of like block quoting on a blog) made this app very enjoyable.
What Is Missing
Unlike the web interface, Tumble lacks the ability to upload audio onto ones post, a fearure that would make this app really shine.
Also users are unable to edit their posts, although that may be due to the fact that Bitfire may not lack access to Tumblr’s full code (beyond the API).
The only bug I discovered was that whenever you log in, the app does not inform you that you have connected to your account.
Update: BitFire Systems has released an update that fixes this bug.
Overall this app was fairly east to use, and Tumblr fans will definately enjoy using this app, as it gives them the ability to richly publish their thoughts away from their computers.
This review was written on the iPhone, with brief editing done from the desktop.