You might be interested in having a look at the mozex plugin for mozilla which lets you plug in external programs into mozilla. Here is the
review that drew my attention to it.

It installs with out a hitch. I have set up the textarea option so to edit a text area all I do is right click on the text area chose mozex -> textarea and the content of the text is openned in gvim. You can then just edit the content and when you save just left click on the text area and the changes appear. Makes it easier than having to select all ctrl c etc to edit text area content in you favourite editor. I also tried it with quanta.