Open source cross-browser HTML editor

I found this great HTML editor for both IE and Mozilla! Their version 3 (current release candidate) works in IE 5.5+ in Windows and Mozilla 1.3 in all OS. It has lots of customisation features and you can even add your own buttons and plugins. It comes with a CSS plugin, that I use to let users set styles, eliminating the font types and sizes (none of us like the <font> tag, right?). And the best is that it makes XHTML valid code.

Another great feature is that it can clean the code copied from Word (which is really messy). Since users will very frequently paste content from their Word docs, this is really important if you want to keep your code nice and clean.

Although I use it in ColdFusion pages, I installed an image manipulation plugin in php. Not so much because I needed the cropping and resizing of pictures, but because it allows users to browse directories and upload pictures (which is not included in the regular distribution) from a very intuitive user interface.

It is also translated into 30 different languages for those who care about internationalization.