Marking this down here so I'll remember it when I do eventually need it.
Teleprompt+, from Bombing Brain Interactive, looks like a nice collection of Mac, iPad and iPhone apps to help with the unenviable task of getting someone to talk on video and appear natural while making sure they don't go off the tracks with what they're saying.
- Teleprompt+ for Mac is $24.99 in the Mac App Store
- Teleprompt+ for iPhone is $7.99 in the iTunes App Store
- Teleprompt+ for iPad is $14.99 in the iTunes App Store