Head over to David Davies' weblog for a detailed guide to setting things up for moblogging.

Although this manual is a thinly-veiled advertisement for Radio Userland, the two-step concept of moblogging it relates holds true for other platforms. Set your blog to monitor an e-mail account for new messages. Next, use a smartphone or PDA phone to send your new posts to that e-mail account. Your blog will automatically publish any new messages it finds.

A plug-in makes it easier for Wordpress users, and the same is true for Movable Type.