haha, like i did on my info packet?
<shameless plug>
http://www.harker-robotics.org/hrtpacket04web.pdf</shameless plug>
make a rounded rectangle, and position it over the picture. then select both of them and go to edit -> clipping mask -> make.
and you're set. if you wanna get rid of it, select it and go to edit -> clipping mask -> release
done.
oh, and for importing pictures. there's no "proper" way to do it. copying and pasting works, as does opening it illustrator (by dragging the file onto the app) and copying and pasting between documents (don't know if that's better than the other, but that's the way i do it. illustrator seems to have its own clipboard, so it might be better.)