Figure 1 - Editor window in Firefox 1.5 with Spellbound extension installed
With the sidebar open, you can create a new annotation with the "Create Annotation" option of the Annotations menu. If there is a region of the document selected, then that region will be annotated; otherwise the entire document will be annotated.
Alternatively, you can select a region of the document in the main window, and select "Annotate current selection" from the context (right-click) menu.
The menu options allow you to create bold, italic, or underlined text, unordered (bulleted) or ordered lists. Spelling checking is available in Mozilla, and can be installed separately on Firefox 1.5.
Figure 1 - Editor window in Firefox 1.5 with Spellbound extension installed
You can add spell-checking support to Firefox 1.5 with the Spellbound extension. (The extension does not yet support the inline spelling checking of Firefox 2.)
After loading the list of annotations in the sidebar, you can select "Edit annotation body" from the right-click (context menu). The interface is essentially the same as that used when creating annotations.