They may be bought but Mark Russinovich is still at it; he and Bryce Cogswell released another new tool under the sysinternals name this week. The tool is called ADExplorer and, as you might guess from the name, it allows you to explore your Active Directory store.
The interface features a windows explorer style interface, and allows you to view, search, and edit things (assuming you have appropriate permissions). So far nothing really new, there are lots of ADSI based viewers in addition to the administrator mmc snapin.
ADExplorer allows you to save a snapshot of the datastore and browse it as well. Probably most important, you can compare the snapshot against your live system. Ever have a persistent issue that required dcdiag to fix now and then and wish you could find what had changed? Bingo! You probably don't even have to snapshot in advance of the problem. Take the snapshot, dcdiag fix, then compare and find what was fixed. Like you expext of a sysinternals tool it is free (see license) and there is no installer, just an exe, help file, and EULA.
One last note. It is, well, ...... slow ........ We're talking AD to here.