MESSAGING: No idea.

CAMERA/VIDEO:
Open the camera cover,
Tap the second icon on the bottom left of the camera application (next to the image remaining counter),
Tap "memory in use" and choose Memory card.

Incidentally, I didn't know that is how you do it - I just looked for it and found it in about 5 seconds as its not like there are that many options in the camera application to get lost.

I really wish people would show some initiative.