On January 17th, 2011 I wrote about a script I wrote to gather information on my network (http://www.anthonyreinke.com/?p=384). I ran the scan a few time with a lot of errors. The issues were due to the different domains. It can’t scan all the machines since it runs as the person running. It doesn’t have the ability to try multiple different credentials.
So I started looking for products to get the information. After a lot of trail and errors I found Lansweeper. This software gives you the incite in to your network that is hard to find. It not only scans the machines, but active directories as well. As for the price, it is hard to bet at $299 per year.