My webhost doesn’t run PHP 5 so I can’t experiment with Elias Torres’ APP client for WordPress here. I was able to post to a test install of WordPress on my PowerBook running PHP 5.
ETA: there’s an updated version that runs on PHP 4.4.x.
ETA 2: And it works, too. I just tried it with Tim Bray’s APE.
And congratulations to the Torres’ on the occasion of the birth of their third child (Elias should confer with Tim and Lauren on the logistics of open source development while taking care of an infant.)