Is it possible to display a dialog box while having applescript perform some action, the automatically close the dialog box when finished?
Unless this has been changed in the last rev of AppleScript, the answer is no. There might be workarounds, but none of them would be pretty.
What you
might be able to do is tell AppleScript to display a dialog but not wait for dismissal by using
ignore (i.e. to run asynchronously). But
ignore may only work with responses from other applications (not sure), so the dialog may have to be generated by a separate application (could be an AppleScript droplet). You can see how even this is starting to get ugly.
Check out the AppleScript links on
Things Macintosh, Developer page for a more definitive answer to your question.