As far as video clips, you should be able to send them like any mms on any phone. Just record the video, long press the video file, choose SHARE, and pick Messages or whichever SMS/MMS app you use.
For screen shots, Google search how. It requires downloading the Android SDK development pack to your PC, Mac or Linux box, get the absolute latest updates, then enable debugging. It's a long process the first time, but if you do it once it'll take 30sec for any future screen shots.
