Notepad++ is a free (as in "free speech" and also as in "free beer") source code editor and Notepad replacement that supports several languages. Running in the MS Windows environment, its use is governed by GPL Licence.

This is a beautiful open-source text editor that can easily double as an HTML editor. It features a tabbed MDI, customizable syntax highlighting, multiple document search & replace, bookmarks, convert to Windows/UNIX/Mac format, file associations manager, customizable keyboard shortcuts, record & playback macros, show all hidden characters and more. It also features syntax folding which will allow you to specify which parts of your source code to display according to the hierarchy of your HTML elements (which is excellent for newbies who are easily overwhelmed by alot of source code). Another nice feature is how macros are saved to the menu system facilitating easy playback and —in essence— creating user defined buttons. The only drawback is there's no help documentation whatsoever so you're basically on your own with the exception of the Notepad++ user forum to which you can post questions or comments.