Awesome app for Reddit also does Tumblr publishing. Boom.

There's also an iPhone version: http://j.mp/xMGOxB

The Tumblr Garden isn't the only place to get Tumblr themes. ThemeForest is the largest 3rd-party directory I know of. There's a lot of good stuff here, and prices range from around $10-35.

You know those tweet and like buttons on just about every site? Tumblr has its own, and you can customize it a bit.

Good—but not great—universal app for posting to and reading Tumblr on iPhone and iPad. It supports some handy perks, like customizing your tweet for each post and writing in Markdown. Plus, at least for now, it's the only decent Tumblr client for iPad.

Tumblr built a tool for meeting your add and edit tags to groups of posts. Pretty handy if you need to do some cleanup.

Possibly another option. Lets you write a log of corresponding URLs for redirection, can also set WP drafts to be private in Tumblr so you can still edit and publish.

Exports a Tumblr blog to a WordPress-friendly XML file. Suited for both WordPress.com and self-hosted versions, though I don't understand what the difference is when it comes to making this file.