Paper Curl Shadow

[jpdp]

what's the easiest way to make a paper curl shadow?
seems like it is common on Mac's and when using Keynote on the Mac
I was thinking of using the mould tool to create a shadow and then put that behind my screenshot, but if there is an easier way, I would love to know.
One that looks like the attached.

[steve.ledger]

Create a black rectangle, convert it to editable shapes, use the shape tool to pull up the bottom line to make a slight arc.
Use a combination of the feather tool and linear transparency tool then position it behind your main object to suit.

[iagman]

jpdp,
I feel curl shadows are more effective when offset and adding to the illusion
that the light source is not directly overhead. Adding a bit of shading to
the paper can also help.