Creating an action from a date trigger

Certainly, do you want this to happen when the PDF is opened?

Add a document level script:

var oDateTrigger = new Date("11/20/2010");
var oToday = new Date();
if(oToday > oDateTrigger)
{
... Do something ...
}

You can do any of the things you've mentioned. Which one do you want?

If it's already open and a particular date occurs OR when it is opened, would be ideal, but I'll certainly settle for just opening the document. The PDF I send out is set to expire in 45 days, but there is a new document available within 30 +/- days. I really would like to launch a pop-up window telling them that it's time to get the new document (with a link to the url) or alternatively to take them to a page in the pdf where those same instructions would be available. That's less desirable since that page would always be available, and there would be no customized message there telling them it's time to upgrade as the file itself cannot be altered since it has heavy heavy security on it (FileOpen).

Here'a the JavaScript function for opening an URL

app.launchURL("http://www.pdfscripting.com");

But how do I trigger it on a particular date? That's my big issue.

Well, that's what the first script was for. Like this:

var oDateTrigger = new Date("11/20/2010");
var oToday = new Date();
if(oToday > oDateTrigger)
{
app.launchURL("http://www.pdfscripting.com");
}

I apologize if it's a newbie question, but is this placed as a custom property that is added into the document?

There is tutorial on entering document level scripts, which are run when the PDF is opened in Acrobat.

http://acrobatusers.com/tutorials/2007/07/js_document_scripts

Just create a script and copy and past the code above into it. Adjust the parameters for what you need

Awesome, Thom!! Thank you SO much!!!