How do you get them off the phone? I have not found a way.
I was yanking your chain, a little. But since you asked...Many phones have software available (either aftermarket or included with the phone) that allow you to dump messages to your pc. You can also forward your messages to your email address. Some other providers will allow you to access your phone's messages from a proprietary website.
Lastly, and this is important. There's quite a few USB-based aftermarket devices that can be plugged into your phone (or connected via WiFi) that will strip all data (including even deleted texts) from the phone itself. Nothing is secure in the world of technology, especially cell phone data.