I've just finished writing a script meant for relaying cell phone MMS (Multimedia Messaging Service) messages to LiveJournal. It's meant to be a procmail plugin, and it's only useful if you can receive email on a shell account that has webspace associated with it. This is especially useful if you have a cameraphone; it is meant for posting a picture and some text.
It should be general enough to work with most service providers. I've only been able to test it with T-Mobile. If you want to play with it, it's available for download here.