OK, hoping this is a quick one...!

I want to add to an excel spreadsheet a way to identify if someone has the file open (without trying to open it myself). Only idea I have is to create macro that creates a text file when the document opens, then another to delete the file when the document closes. Any ideas??

You could do that or create a log file to list each time the file is opened and closed.

If you Make the file a Shared File, then you can open the Shared file dialog and see who has the file open. But this requires you to have the file open to view the shared users information.