This time I'm using a great mobile blogging freebie called u*Blog.
Initially I thought it did not have a Category feature but it looks like I am mistaken. The settings are in the 'spanner symbol' when one makes a new post. If you are posting to your own webhosting, u*Blog can also upload images.
Feature for feature, u*Blog seems to match mo:blog. The best part is it's free! Kudos to the author. Looks like this one is a keeper.