Altova also has a free XML Editing Tool. It is the home version of XMLSpy - (I believe the professional version is the tool that Firaxis used for Civ4).
It is way too complex for me - it says it can convert XLM files to XLS files. The Text editor is what I got it for - it is much better that WordPad as there are color schemes. It will also Validate the XML file. You can also view the XML file as an html file.
Anyway, here is the link to the Free Home XMLSpy page. (They do ask for personal info in order to download it - but the app is fully functional and free.) ( I am not associated in any way with ths company.)
http://www.altova.com/download_components.html