OK, I went ahead and splurged the $2 for this app.
It’s pretty good. UI is rough, and I’m waiting to hear from the dev about how to rotate video because it shows correctly on my old phone working as a web cam, but it is 90° rotated on the MJPEG stream.
But it supports DDNS, can trigger remote recording (to the camera’s storage) and has other nice features including audio streaming!
For $2, you can turn every one of your old iOS devices into cameras.
EDIT: This keeps getting better!
Don’t let the “main” page showing you frakking Flash. Use Live Stream 2.
You can access recordings on the phone in the browser.
This makes your phone appear as a bonjour device.
Update: Turns out the camera only displays in portrait mode, and for some reason they chose to have it be oriented so you have to have the iOS device with the side that has the volume controls on the bottom.
Hopefully this will be fixed in an update because some people might want portrait mode. To use the phone as a cam in a cradle, for example.