Here is something that is very, very cool! Pranav Wagh has built a much improved version of OpenXmlDiff, with a graphical user interface. And its free, already built (binaries available) on code.msdn.com/OpenXMLDiff.
here.)(Oct 27, 2008 - The Open XML SDK development team has built an Open XML Diff program that's very nice - find out about it
When you start the program, you see a dialog box:
When you look at the HTML output, you see a beautiful window with deletions in red, additions in yellow, changes in green:
This program has all of the options I want or need: can select which types of changes to see, control type of output, and more.
This completely obviates my simple, crude OpenXmlDiff. Pranav's utility now has a permanent spot in my toolkit. I have it in my quick launch.
If you are a developer who works with Open XML, read his post, and download his utility. Nice job, Pranav!