Excel file posted to shared drive, cannot save changes while other users have file open

I've seen this mentioned in posts here, and I'm sure this situation is common. But how can I fix, address, or work around this? Is there a best practice for this?
I need to be able to save changes to the spreadsheet and can't count on all the users to not have the file open.
I think a possible solution I've seen is to just save a copy of the file to the shared drive for the read-only users to view, or to make a macro that will auto-save a copy out on the share drive when I edit the original file. But in these cases I still deal with the same issue if a user has the file opened.
How do people deal with this problem?
Any help is appreciated,
Thanks,
Ari

Click on the Review tab, turn on "Share Workbook".

Would the "Share Workbook" feature work for me? I need to allow all network users to open and the workbook, but only I can change it. I need to be able to save changes to it while other users may have it open to read.
Looking at the "Share Notebook" feature's description, it looks like it might either allow other users to edit the notebook, or require a password for them to open it. I don't want to have to require a password for users to open and read it.
Is Share the right way to accomplish this? How do I implement that?
Thanks again,
Ari

I don't know if this will help you or not but I just done about the same thing on what I think has been a major effort on my part as I am just learning this program. But you can assign certain individuals permission and allow only certain people access. When you select a person you can then choose what privileges you allow them such as read only, write, modify etc. Thus maintaining your total control of the document. So select your file, go to properties and then security. That is were you select the people and assign access. Hope it helps

So, I've already set the windows file permissions. This is what you get when you select the file in windows explorer, right click it, choose properties, and then go to security. It is set to 'read only' for all users, but Network Administrators and I have full permissions.
In Excel, if I go to File and select to protect the Workbook, it seems I would have to give each person access individually by their email addresses. Again, I would like everyone who can access that network share to be able to read this workbook. I don't want to have to keep up a list of people to let them sign in with Live and read it (a few hundred people?).
I still want to be able to save changes to it myself even if they have it open for reading.
Is there a way to use the protect workbook feature to allow "everyone" read access without specifying them individually?