Added 040813: A quick note to respond to Judy's query: I successfully use XML Notepad 2007 on Windows 7 today – here’s the DL link: http://www.microsoft.com/en-us/download/details.aspx?id=7973. Although it's not expressly called out as compatible, there are a number of older utilities that may not have been formally tested with Windows 7, but work just fine (or via compatibility mode). BTW, I use Windows 7, Windows Server 2012, Windows Phone (7.x and 8), and Windows 8 (RT and x86) at the office.
A shout out on a new, refound favourite application: Microsoft XML Notepad 2007, a simple intuitive user interface for browsing and editing XML documents.
Here's a little history on XML Notepad from Chris Lovett: http://msdn.microsoft.com/en-us/library/aa905339.aspx
"I finally got around to fulfilling a promise I made to a friend at MSDN. Back in 1998, we shipped an XML Notepad, written by Murray Low in C++. Later on it fell behind in support for XML standards and, because we didn't have time to fix it, we pulled it off MSDN. But Murray apparently did such a nice job that MSDN was inundated with requests to put the notepad back up, so MSDN asked me for a replacement.
"I've been working on System.Xml in C# since 1999, so I figured I could crank out a replacement using the .NET Framework pretty quickly. Well, the problem was it was one of those side projects on my "one-day" list — you know how that goes! Fortunately, a good friend of mine, Michael Corning, took interest in it, helped hold my feet to the fire, and also added some cool features himself. Dan Doris also took pity on me and helped identify some great bugs. So here we are, finally, with something that should be useful to those who want a quick way to view and edit XML documents.
"For those who know the original version, the interface should look familiar: a tree view on the left synchronized with a node text view on the right and handy nudge toolbar buttons for quick movement of nodes up and down the tree (see Figure 1). Because it's been so long since the first version, I've had to leverage the cool stuff in System.Xml and add some bells and whistles that the original version didn't have:"
- Incremental search (CTRL+I) in both tree and text views, so that as you type it navigates to the most matched node.
- Cut/copy/paste with full namespace support in a simple interoperable XML format.
- Drag/drop support for easy manipulation of the tree, even across different instances of XML Notepad and from the file system.
- Infinite undo/redo for all edit operations.
- In-place, pop-up, multi-line editing of large text node values and IntelliSense based on expected elements and attributes.
- Configurable fonts and colors via the options dialog.
- Full find/replace dialog with support for regex and XPath expressions.
- Good performance on large XML documents (loading a 3 MB document in about one second).
- Instant XML schema validation while you edit with errors and warnings shown in the task list window.
- Support for custom editors for date, dateTime, time, and color datatypes.
- HTML viewer for displaying XSLT transformation results.
- Built-in XML Diff tool.
Also available via http://bit.ly/9u9bGX