David Hogue and Mariano Ferrario have build an Annotations panel for Fireworks CS5. The extension can be downloaded as a free lite version and full paid ($1.99)version form their website.
“The annotations panel is an easy to use command panel that helps you increase the efficiency of annotating wireframes (adding notes) within your Fireworks document (CS5 Only).
The panel allows you to add numeric bubbles to your document and associate a corresponding message with each annotation. The annotation panel then allows you to export your document along with all of your annotations in multiple file formats.”
It is an extension which is sure to increase your efficiency. This also exposes the powerful extensibility layer embedded within Fireworks app.