J.,
There are a couple options available to do what you are asking. The easiest is to use the built in Search feature of EIOBoard where you can filter by the Status. You just select the status of "In" and it will show you all the users that are currently in.
What you described is the reason our EIOBoard Offline Interface was developed. In a true emergency you may not have the time or capability to run a report to see who is in. The EIOBoard Offline Interface keeps a local copy of your EIOBoard database on a Windows Mobile device so you can grab the device and go, even if your EIOBoard server and/or network is unavailable. You can read more about this here:
http://www.eioboard.com/Products/So...rface.aspx