Scott - LDAP integration is being planned for the next release (in May or June of '09).
How the database works is basically when a new "person of interest" is added to an incident report (either a person involved or a witness) that person is checked to see if they've ever been entered before, now keep in mind the program smartly scans the database for a name match while you type in a persons name - this is called the auto complete feature
http://www.asp.net/AJAX/AjaxControlToolkit/Samples/AutoComplete/AutoComplete.aspx - if a match is found the form gets automatically filled in with the closest match, for example if I start typing my name into a report "Patrick McKula" after 3 characters are typed in ... P A T - all entries that exist with PAT anywhere in the name will appear in a list under the text box, as you type more characters the choices narrow - you either select a choice listed or type in your own new name. This prevents typos and duplicate entries.
This match search runs against the in incident tracker database for each client setup. We are working on a way to scan an existing LDAP service; so possibly in the future your scan can go against a enterprise database of users. But at the end of the day incident tracker does create it's own database of users, so queries against names during an advanced search do not take an outrageously long time to complete, which might be the case if the search parsed against an existing enterprise database of 30,000 users - which could be the case if the program didn't build it's own database but rather used an LDAP database of users.
I hope that makes sense, please feel free to ask more questions about this and we will be sure to answer them all for you. Thanks for your inquiry.
Pat