Create an expiring PDF

"It looks like Adobe is trialing a new service that might just fit your needs - Adobe's ""Protect an Adobe PDF File"" service:

What is the Protect an Adobe PDF File
service?

Protect an Adobe PDF File is
an online service that allows you to
protect your Adobe PDF documents in
powerful new ways. Once your PDF files
have been protected using the Protect
an Adobe PDF File service, you retain
complete control over who can access
your files and what actions the users
of your documents may take. You even
have the ability to modify allowable
actions or revoke access to protected
Adobe PDF files altogether after you
have distributed your documents.

What exactly does Protect an Adobe PDF
File allow me to do?

The Protect an
Adobe PDF File service allows you to
apply persistent usage rights settings
to the PDF file itself. For example,
you can:


Specify exactly who can open a protected Adobe PDF file, regardless
of how the file is received,
Restrict the types of actions that users can take (such as no
printing, no copying, or no redlining
and commenting),
Specify a time period during which the file can be accessed by
users,
Revoke access to copies of the document even after you have
distributed such copies, and
Track events related to the copies you have distributed, such as
when they were accessed, who accessed
them, and more.


How much does the service cost?

The Protect an Adobe PDF File service
is currently in beta. During the
initial beta period, it is available
at no extra cost to Create Adobe PDF
Online subscribers. Subscription rates
and other charges may be applied at
the end of this period.

The Protect an Adobe PDF File service
is also available now to trial users
of Create Adobe PDF Online.

Looks like right now you have to be a part of Adobe's online PDF creation service."