To anticipate an email from Google, I must say that Blogger didn't launch a version that works offline, so the tool described in this post is only an example of what you can do using the recently-launched Blogger JavaScript library. The new library lets you create applications that interact with the account of a Blogger user: retrieve his blogs, edit existing posts, or create new posts. Basically, you can create a different Blogger editor by only writing JavaScript code.
Blog.gears is an example of Blogger editor that uses Google Gears to make it work offline. You're able to create blog posts and edit one of the recent posts even if you don't have an Internet connection. As soon as you go back online, Blog.gears synchronizes the data stored offline with the data from Blogger's servers. There's nothing fancy about the editor (no rich-text editor, you can't add images or preview the post), but it's a cool preview of what we can expect from a new version of Blogger that will be offline-enabled.
A more advanced blog editor that works offline and it's not restricted to Blogger is Windows Live Writer. "Writer synchronizes drafts on your blog with changes you make when you're offline, so you don't have to worry about reconciling different versions."
