There's been a bunch of wierd things going on with MMS lately. I'm sure it has something to do with compatibility issues with SMS. At any rate, barring any issues with a slow connection, I've encountered the "Schedule Message" direction a lot lately. If I go ahead and schedule the message, without picking a time to schedule mind you, the message goes through pretty quickly. It happens with any message, including pictures via text.
I have no idea what is causing this. I'm normally on wifi at the house, so I'm kinda ruling out Verizon, but who knows.