How do I crop a photo in Illustrator?

I can't believe I can't figure this out. (I came over from Freehand, and it was simple).

All I want to do is:
1) Crop a placed photo within Illustrator
2) Create a border around it.

I can't seem to find the answer in any help file. Is it so simple in Illustrator that they don't explain how to do it? I don't want to create crop marks for the entire image, just crop off part of a photo without going back into Photoshop. How?

Thanks very much.

Mark