Its not exactly WordPress for Windows Mobile, but if you maintain a blog on LiveJournal and have a Windows Mobile phone this may be the software you have been waiting for.
The software first showed up in a Russian handset by Rover, but now appears to have been made available for wider consumption.
LiveJournal 1.0 for Windows Mobile lets you:
* Read Friends Pages
* Post to your Journal or Communities
* Leave comments
* Post photos
* Communicate via personal messages
Download the software and try it for yourself at FreewarePocketpc.net here.